1261650000 has 240 divisors, whose sum is σ = 4393968768. Its totient is φ = 310080000.

The previous prime is 1261649969. The next prime is 1261650011. The reversal of 1261650000 is 561621.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (240).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1949677 + ... + 1950323.

Almost surely, 2^1261650000 is an apocalyptic number.

1261650000 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 1261650000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2196984384).

1261650000 is an abundant number, since it is smaller than the sum of its proper divisors (3132318768).

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

1261650000 is an equidigital number, since it uses as much as digits as its factorization.

1261650000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 696 (or 670 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 1261650000 is about 35519.7128366770. The cubic root of 1261650000 is about 1080.5535571022.

The spelling of 1261650000 in words is "one billion, two hundred sixty-one million, six hundred fifty thousand".