21106638374 has 4 divisors (see below), whose sum is σ = 31659957564. Its totient is φ = 10553319186.

The previous prime is 21106638361. The next prime is 21106638389. The reversal of 21106638374 is 47383660112.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5276659592 + ... + 5276659595.

It is an arithmetic number, because the mean of its divisors is an integer number (7914989391).

Almost surely, 2^21106638374 is an apocalyptic number.

21106638374 is a deficient number, since it is larger than the sum of its proper divisors (10553319190).

21106638374 is a wasteful number, since it uses less digits than its factorization.

21106638374 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10553319189.

The product of its (nonzero) digits is 145152, while the sum is 41.

The spelling of 21106638374 in words is "twenty-one billion, one hundred six million, six hundred thirty-eight thousand, three hundred seventy-four".