21425399207731 has 2 divisors, whose sum is σ = 21425399207732. Its totient is φ = 21425399207730.

The previous prime is 21425399207669. The next prime is 21425399207767. The reversal of 21425399207731 is 13770299352412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21425399207731 - 2²³ = 21425390819123 is a prime.

It is a super-2 number, since 2×21425399207731² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21425399207431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10712699603865 + 10712699603866.

It is an arithmetic number, because the mean of its divisors is an integer number (10712699603866).

Almost surely, 2^{21425399207731} is an apocalyptic number.

21425399207731 is a deficient number, since it is larger than the sum of its proper divisors (1).

21425399207731 is an equidigital number, since it uses as much as digits as its factorization.

21425399207731 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5715360, while the sum is 55.

The spelling of 21425399207731 in words is "twenty-one trillion, four hundred twenty-five billion, three hundred ninety-nine million, two hundred seven thousand, seven hundred thirty-one".