21221017100858 has 4 divisors (see below), whose sum is σ = 31831525651290. Its totient is φ = 10610508550428.

The previous prime is 21221017100813. The next prime is 21221017100923. The reversal of 21221017100858 is 85800171012212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 14958275613649 + 6262741487209 = 3867593^2 + 2502547^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5305254275213 + ... + 5305254275216.

Almost surely, 2^{21221017100858} is an apocalyptic number.

21221017100858 is a deficient number, since it is larger than the sum of its proper divisors (10610508550432).

21221017100858 is a wasteful number, since it uses less digits than its factorization.

21221017100858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10610508550431.

The product of its (nonzero) digits is 17920, while the sum is 38.

The spelling of 21221017100858 in words is "twenty-one trillion, two hundred twenty-one billion, seventeen million, one hundred thousand, eight hundred fifty-eight".