21011511239 has 2 divisors, whose sum is σ = 21011511240. Its totient is φ = 21011511238.

The previous prime is 21011511229. The next prime is 21011511281. The reversal of 21011511239 is 93211511012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21011511239 - 2²⁴ = 20994734023 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21011511229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505755619 + 10505755620.

It is an arithmetic number, because the mean of its divisors is an integer number (10505755620).

Almost surely, 2^21011511239 is an apocalyptic number.

21011511239 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011511239 is an equidigital number, since it uses as much as digits as its factorization.

21011511239 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 540, while the sum is 26.

The spelling of 21011511239 in words is "twenty-one billion, eleven million, five hundred eleven thousand, two hundred thirty-nine".