1261517660 has 96 divisors (see below), whose sum is σ = 2975797440. Its totient is φ = 446164992.

The previous prime is 1261517651. The next prime is 1261517669. The reversal of 1261517660 is 667151621.

It is an interprime number because it is at equal distance from previous prime (1261517651) and next prime (1261517669).

It is a self number, because there is not a number n which added to its sum of digits gives 1261517660.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261517669) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 591476 + ... + 593604.

It is an arithmetic number, because the mean of its divisors is an integer number (30997890).

Almost surely, 2^1261517660 is an apocalyptic number.

1261517660 is a gapful number since it is divisible by the number (10) 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 1261517660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1487898720).

1261517660 is an abundant number, since it is smaller than the sum of its proper divisors (1714279780).

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

1261517660 is a wasteful number, since it uses less digits than its factorization.

1261517660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2247 (or 2245 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 1261517660 is about 35517.8498786174. The cubic root of 1261517660 is about 1080.5157744477.

The spelling of 1261517660 in words is "one billion, two hundred sixty-one million, five hundred seventeen thousand, six hundred sixty".