21021200012551 has 8 divisors (see below), whose sum is σ = 23089647611520. Its totient is φ = 19048959278712.

The previous prime is 21021200012539. The next prime is 21021200012557. The reversal of 21021200012551 is 15521000212012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21021200012551 - 2²⁵ = 21021166458119 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021200012557) 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, 24051715825 + ... + 24051716698.

It is an arithmetic number, because the mean of its divisors is an integer number (2886205951440).

Almost surely, 2^{21021200012551} is an apocalyptic number.

21021200012551 is a deficient number, since it is larger than the sum of its proper divisors (2068447598969).

21021200012551 is a wasteful number, since it uses less digits than its factorization.

21021200012551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48103432565.

The product of its (nonzero) digits is 400, while the sum is 22.

Adding to 21021200012551 its reverse (15521000212012), we get a palindrome (36542200224563).

The spelling of 21021200012551 in words is "twenty-one trillion, twenty-one billion, two hundred million, twelve thousand, five hundred fifty-one".