21890409812 has 12 divisors (see below), whose sum is σ = 39543966336. Its totient is φ = 10592133720.

The previous prime is 21890409769. The next prime is 21890409841.

21890409812 is nontrivially palindromic in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 88267658 + ... + 88267905.

It is an arithmetic number, because the mean of its divisors is an integer number (3295330528).

Almost surely, 2^21890409812 is an apocalyptic number.

It is an amenable number.

21890409812 is a deficient number, since it is larger than the sum of its proper divisors (17653556524).

21890409812 is a wasteful number, since it uses less digits than its factorization.

21890409812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176535598 (or 176535596 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 44.

The spelling of 21890409812 in words is "twenty-one billion, eight hundred ninety million, four hundred nine thousand, eight hundred twelve".