21375620494 has 4 divisors (see below), whose sum is σ = 32063430744. Its totient is φ = 10687810246.

The previous prime is 21375620491. The next prime is 21375620503. The reversal of 21375620494 is 49402657312.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21375620494.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21375620491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5343905122 + ... + 5343905125.

It is an arithmetic number, because the mean of its divisors is an integer number (8015857686).

Almost surely, 2^21375620494 is an apocalyptic number.

21375620494 is a deficient number, since it is larger than the sum of its proper divisors (10687810250).

21375620494 is a wasteful number, since it uses less digits than its factorization.

21375620494 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10687810249.

The product of its (nonzero) digits is 362880, while the sum is 43.

The spelling of 21375620494 in words is "twenty-one billion, three hundred seventy-five million, six hundred twenty thousand, four hundred ninety-four".