21920758507 has 4 divisors (see below), whose sum is σ = 21921467256. Its totient is φ = 21920049760.

The previous prime is 21920758493. The next prime is 21920758523. The reversal of 21920758507 is 70585702912.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21920758507 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21920758537) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 305758 + ... + 370579.

It is an arithmetic number, because the mean of its divisors is an integer number (5480366814).

Almost surely, 2^21920758507 is an apocalyptic number.

21920758507 is a deficient number, since it is larger than the sum of its proper divisors (708749).

21920758507 is an equidigital number, since it uses as much as digits as its factorization.

21920758507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708748.

The product of its (nonzero) digits is 352800, while the sum is 46.

The spelling of 21920758507 in words is "twenty-one billion, nine hundred twenty million, seven hundred fifty-eight thousand, five hundred seven".