21050551661204 has 12 divisors (see below), whose sum is σ = 39672193515444. Its totient is φ = 9715639228224.

The previous prime is 21050551661201. The next prime is 21050551661221. The reversal of 21050551661204 is 40216615505012.

It can be written as a sum of positive squares in 2 ways, for example, as 9675770148100 + 11374781513104 = 3110590^2 + 3372652^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21050551661201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 202409150537 + ... + 202409150640.

It is an arithmetic number, because the mean of its divisors is an integer number (3306016126287).

Almost surely, 2^{21050551661204} is an apocalyptic number.

It is an amenable number.

21050551661204 is a deficient number, since it is larger than the sum of its proper divisors (18621641854240).

21050551661204 is a wasteful number, since it uses less digits than its factorization.

21050551661204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404818301194 (or 404818301192 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 38.

The spelling of 21050551661204 in words is "twenty-one trillion, fifty billion, five hundred fifty-one million, six hundred sixty-one thousand, two hundred four".