21439257202729 has 2 divisors, whose sum is σ = 21439257202730. Its totient is φ = 21439257202728.

The previous prime is 21439257202667. The next prime is 21439257202747. The reversal of 21439257202729 is 92720275293412.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19805819839129 + 1633437363600 = 4450373^2 + 1278060^2 .

It is a cyclic number.

It is not a de Polignac number, because 21439257202729 - 2²³ = 21439248814121 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21439257202729.

It is not a weakly prime, because it can be changed into another prime (21439257206729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10719628601364 + 10719628601365.

It is an arithmetic number, because the mean of its divisors is an integer number (10719628601365).

Almost surely, 2^{21439257202729} is an apocalyptic number.

It is an amenable number.

21439257202729 is a deficient number, since it is larger than the sum of its proper divisors (1).

21439257202729 is an equidigital number, since it uses as much as digits as its factorization.

21439257202729 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7620480, while the sum is 55.

The spelling of 21439257202729 in words is "twenty-one trillion, four hundred thirty-nine billion, two hundred fifty-seven million, two hundred two thousand, seven hundred twenty-nine".