21621542540633 has 24 divisors (see below), whose sum is σ = 25929152661384. Its totient is φ = 17965568275200.

The previous prime is 21621542540621. The next prime is 21621542540641. The reversal of 21621542540633 is 33604524512612.

It can be written as a sum of positive squares in 4 ways, for example, as 3062230505929 + 18559312034704 = 1749923^2 + 4308052^2 .

It is not a de Polignac number, because 21621542540633 - 2⁶ = 21621542540569 is a prime.

It is a super-2 number, since 2×21621542540633² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21621542540683) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 33959558 + ... + 34590383.

It is an arithmetic number, because the mean of its divisors is an integer number (1080381360891).

Almost surely, 2^{21621542540633} is an apocalyptic number.

It is an amenable number.

21621542540633 is a deficient number, since it is larger than the sum of its proper divisors (4307610120751).

21621542540633 is a wasteful number, since it uses less digits than its factorization.

21621542540633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68550153 (or 68550146 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 44.

The spelling of 21621542540633 in words is "twenty-one trillion, six hundred twenty-one billion, five hundred forty-two million, five hundred forty thousand, six hundred thirty-three".