21621411656536 has 32 divisors (see below), whose sum is σ = 41127473368800. Its totient is φ = 10654866576640.

The previous prime is 21621411656531. The next prime is 21621411656587. The reversal of 21621411656536 is 63565611412612.

It is a self number, because there is not a number n which added to its sum of digits gives 21621411656536.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621411656531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48600355 + ... + 49043218.

It is an arithmetic number, because the mean of its divisors is an integer number (1285233542775).

Almost surely, 2^{21621411656536} is an apocalyptic number.

It is an amenable number.

21621411656536 is a deficient number, since it is larger than the sum of its proper divisors (19506061712264).

21621411656536 is a wasteful number, since it uses less digits than its factorization.

21621411656536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97643979 (or 97643975 counting only the distinct ones).

The product of its digits is 1555200, while the sum is 49.

The spelling of 21621411656536 in words is "twenty-one trillion, six hundred twenty-one billion, four hundred eleven million, six hundred fifty-six thousand, five hundred thirty-six".