21526601556990 has 64 divisors (see below), whose sum is σ = 53910870354432. Its totient is φ = 5490764611200.

The previous prime is 21526601556983. The next prime is 21526601557003. The reversal of 21526601556990 is 9965510662512.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 21526601556990.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 59526120 + ... + 59886660.

It is an arithmetic number, because the mean of its divisors is an integer number (842357349288).

Almost surely, 2^{21526601556990} is an apocalyptic number.

21526601556990 is an abundant number, since it is smaller than the sum of its proper divisors (32384268797442).

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

21526601556990 is a wasteful number, since it uses less digits than its factorization.

21526601556990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 447105.

The product of its (nonzero) digits is 8748000, while the sum is 57.

The spelling of 21526601556990 in words is "twenty-one trillion, five hundred twenty-six billion, six hundred one million, five hundred fifty-six thousand, nine hundred ninety".