21009890211 has 16 divisors (see below), whose sum is σ = 28082581248. Its totient is φ = 13971938400.

The previous prime is 21009890207. The next prime is 21009890263. The reversal of 21009890211 is 11209890012.

It is not a de Polignac number, because 21009890211 - 2² = 21009890207 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21009890411) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2439565 + ... + 2448161.

It is an arithmetic number, because the mean of its divisors is an integer number (1755161328).

Almost surely, 2^21009890211 is an apocalyptic number.

21009890211 is a deficient number, since it is larger than the sum of its proper divisors (7072691037).

21009890211 is a wasteful number, since it uses less digits than its factorization.

21009890211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10522.

The product of its (nonzero) digits is 2592, while the sum is 33.

The spelling of 21009890211 in words is "twenty-one billion, nine million, eight hundred ninety thousand, two hundred eleven".