21431007906 has 32 divisors (see below), whose sum is σ = 53438358528. Its totient is φ = 5566495440.

The previous prime is 21431007889. The next prime is 21431007929. The reversal of 21431007906 is 60970013412.

It is a super-3 number, since 3×21431007906³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23193270 + ... + 23194193.

It is an arithmetic number, because the mean of its divisors is an integer number (1669948704).

Almost surely, 2^21431007906 is an apocalyptic number.

21431007906 is an abundant number, since it is smaller than the sum of its proper divisors (32007350622).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21431007906 is a wasteful number, since it uses less digits than its factorization.

21431007906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46387486.

The product of its (nonzero) digits is 9072, while the sum is 33.

The spelling of 21431007906 in words is "twenty-one billion, four hundred thirty-one million, seven thousand, nine hundred six".