21391322738 has 8 divisors (see below), whose sum is σ = 32107570560. Its totient is φ = 10688799220.

The previous prime is 21391322737. The next prime is 21391322741. The reversal of 21391322738 is 83722319312.

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

It is a junction number, because it is equal to n+sod(n) for n = 21391322695 and 21391322704.

It is not an unprimeable number, because it can be changed into a prime (21391322731) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3427178 + ... + 3433413.

It is an arithmetic number, because the mean of its divisors is an integer number (4013446320).

Almost surely, 2^21391322738 is an apocalyptic number.

21391322738 is a deficient number, since it is larger than the sum of its proper divisors (10716247822).

21391322738 is a wasteful number, since it uses less digits than its factorization.

21391322738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6862152.

The product of its digits is 108864, while the sum is 41.

The spelling of 21391322738 in words is "twenty-one billion, three hundred ninety-one million, three hundred twenty-two thousand, seven hundred thirty-eight".