21551532106621 has 32 divisors (see below), whose sum is σ = 24134545351296. Its totient is φ = 19078106112000.

The previous prime is 21551532106613. The next prime is 21551532106661. The reversal of 21551532106621 is 12660123515512.

It is a cyclic number.

It is not a de Polignac number, because 21551532106621 - 2³ = 21551532106613 is a prime.

It is a super-2 number, since 2×21551532106621² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21551532106661) 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, 393816541 + ... + 393871261.

It is an arithmetic number, because the mean of its divisors is an integer number (754204542228).

Almost surely, 2^{21551532106621} is an apocalyptic number.

It is an amenable number.

21551532106621 is a deficient number, since it is larger than the sum of its proper divisors (2583013244675).

21551532106621 is a wasteful number, since it uses less digits than its factorization.

21551532106621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59853.

The product of its (nonzero) digits is 108000, while the sum is 40.

The spelling of 21551532106621 in words is "twenty-one trillion, five hundred fifty-one billion, five hundred thirty-two million, one hundred six thousand, six hundred twenty-one".