1261630656 has 504 divisors, whose sum is σ = 4598206704. Its totient is φ = 325877760.

The previous prime is 1261630633. The next prime is 1261630679. The reversal of 1261630656 is 6560361621.

1261630656 is a `hidden beast` number, since 1 + 2 + 616 + 30 + 6 + 5 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (1261630633) and next prime (1261630679).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 1261630656.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 23804326 + ... + 23804378.

It is an arithmetic number, because the mean of its divisors is an integer number (9123426).

Almost surely, 2^1261630656 is an apocalyptic number.

1261630656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1261630656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2299103352).

1261630656 is an abundant number, since it is smaller than the sum of its proper divisors (3336576048).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1261630656 is a wasteful number, since it uses less digits than its factorization.

1261630656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129 (or 99 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 1261630656 is about 35519.4405361346. The cubic root of 1261630656 is about 1080.5480346158.

The spelling of 1261630656 in words is "one billion, two hundred sixty-one million, six hundred thirty thousand, six hundred fifty-six".