21157231423 has 8 divisors (see below), whose sum is σ = 21197572560. Its totient is φ = 21116921280.

The previous prime is 21157231397. The next prime is 21157231427. The reversal of 21157231423 is 32413275112.

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-21157231423 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 (21157231427) 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, 1703211 + ... + 1715587.

It is an arithmetic number, because the mean of its divisors is an integer number (2649696570).

Almost surely, 2^21157231423 is an apocalyptic number.

21157231423 is a deficient number, since it is larger than the sum of its proper divisors (40341137).

21157231423 is a wasteful number, since it uses less digits than its factorization.

21157231423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15497.

The product of its digits is 10080, while the sum is 31.

The spelling of 21157231423 in words is "twenty-one billion, one hundred fifty-seven million, two hundred thirty-one thousand, four hundred twenty-three".