21723237157 has 2 divisors, whose sum is σ = 21723237158. Its totient is φ = 21723237156.

The previous prime is 21723237103. The next prime is 21723237161. The reversal of 21723237157 is 75173232712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21431203236 + 292033921 = 146394^2 + 17089^2 .

It is a cyclic number.

It is not a de Polignac number, because 21723237157 - 2²⁷ = 21589019429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21723267157) 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, 10861618578 + 10861618579.

It is an arithmetic number, because the mean of its divisors is an integer number (10861618579).

Almost surely, 2^21723237157 is an apocalyptic number.

It is an amenable number.

21723237157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21723237157 is an equidigital number, since it uses as much as digits as its factorization.

21723237157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 123480, while the sum is 40.

Adding to 21723237157 its reverse (75173232712), we get a palindrome (96896469869).

The spelling of 21723237157 in words is "twenty-one billion, seven hundred twenty-three million, two hundred thirty-seven thousand, one hundred fifty-seven".