249628551021 has 12 divisors (see below), whose sum is σ = 381784842972. Its totient is φ = 156629678976.

The previous prime is 249628551017. The next prime is 249628551031. The reversal of 249628551021 is 120155826942.

249628551021 is a `hidden beast` number, since 2 + 4 + 9 + 628 + 5 + 5 + 10 + 2 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 192764902500 + 56863648521 = 439050^2 + 238461^2 .

It is not a de Polignac number, because 249628551021 - 2² = 249628551017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (249628551031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 815779426 + ... + 815779731.

It is an arithmetic number, because the mean of its divisors is an integer number (31815403581).

Almost surely, 2^249628551021 is an apocalyptic number.

It is an amenable number.

249628551021 is a deficient number, since it is larger than the sum of its proper divisors (132156291951).

249628551021 is a wasteful number, since it uses less digits than its factorization.

249628551021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1631559180 (or 1631559177 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The spelling of 249628551021 in words is "two hundred forty-nine billion, six hundred twenty-eight million, five hundred fifty-one thousand, twenty-one".