21765239157 has 8 divisors (see below), whose sum is σ = 30547704160. Its totient is φ = 13746466800.

The previous prime is 21765239149. The next prime is 21765239189. The reversal of 21765239157 is 75193256712.

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

It is not a de Polignac number, because 21765239157 - 2³ = 21765239149 is a prime.

It is a super-2 number, since 2×21765239157² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21765239957) 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 in 7 ways as a sum of consecutive naturals, for example, 190923094 + ... + 190923207.

It is an arithmetic number, because the mean of its divisors is an integer number (3818463020).

Almost surely, 2^21765239157 is an apocalyptic number.

It is an amenable number.

21765239157 is a deficient number, since it is larger than the sum of its proper divisors (8782465003).

21765239157 is a wasteful number, since it uses less digits than its factorization.

21765239157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381846323.

The product of its digits is 793800, while the sum is 48.

The spelling of 21765239157 in words is "twenty-one billion, seven hundred sixty-five million, two hundred thirty-nine thousand, one hundred fifty-seven".