21051691526731 has 2 divisors, whose sum is σ = 21051691526732. Its totient is φ = 21051691526730.

The previous prime is 21051691526711. The next prime is 21051691526809. The reversal of 21051691526731 is 13762519615012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21051691526731 - 2²¹ = 21051689429579 is a prime.

It is a super-2 number, since 2×21051691526731² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21051691526711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525845763365 + 10525845763366.

It is an arithmetic number, because the mean of its divisors is an integer number (10525845763366).

Almost surely, 2^{21051691526731} is an apocalyptic number.

21051691526731 is a deficient number, since it is larger than the sum of its proper divisors (1).

21051691526731 is an equidigital number, since it uses as much as digits as its factorization.

21051691526731 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 680400, while the sum is 49.

The spelling of 21051691526731 in words is "twenty-one trillion, fifty-one billion, six hundred ninety-one million, five hundred twenty-six thousand, seven hundred thirty-one".