21106638373 has 8 divisors (see below), whose sum is σ = 21132631800. Its totient is φ = 21080664000.

The previous prime is 21106638361. The next prime is 21106638389. The reversal of 21106638373 is 37383660112.

It can be written as a sum of positive squares in 4 ways, for example, as 7459258689 + 13647379684 = 86367^2 + 116822^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21106638373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21106638073) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3834123 + ... + 3839623.

It is an arithmetic number, because the mean of its divisors is an integer number (2641578975).

Almost surely, 2^21106638373 is an apocalyptic number.

It is an amenable number.

21106638373 is a deficient number, since it is larger than the sum of its proper divisors (25993427).

21106638373 is a wasteful number, since it uses less digits than its factorization.

21106638373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9527.

The product of its (nonzero) digits is 108864, while the sum is 40.

The spelling of 21106638373 in words is "twenty-one billion, one hundred six million, six hundred thirty-eight thousand, three hundred seventy-three".