261949657000 has 32 divisors (see below), whose sum is σ = 612962199720. Its totient is φ = 104779862400.

The previous prime is 261949656949. The next prime is 261949657003. The reversal of 261949657000 is 756949162.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 66449497284 + 195500159716 = 257778^2 + 442154^2 .

It is not an unprimeable number, because it can be changed into a prime (261949657003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 130973829 + ... + 130975828.

Almost surely, 2^261949657000 is an apocalyptic number.

261949657000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261949657000 is an abundant number, since it is smaller than the sum of its proper divisors (351012542720).

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

261949657000 is a wasteful number, since it uses less digits than its factorization.

261949657000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261949678 (or 261949664 counting only the distinct ones).

The product of its (nonzero) digits is 816480, while the sum is 49.

It can be divided in two parts, 2619496 and 57000, that added together give a square (2676496 = 1636²).

The spelling of 261949657000 in words is "two hundred sixty-one billion, nine hundred forty-nine million, six hundred fifty-seven thousand".