22515915001991 has 2 divisors, whose sum is σ = 22515915001992. Its totient is φ = 22515915001990.

The previous prime is 22515915001817. The next prime is 22515915002023. The reversal of 22515915001991 is 19910051951522.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 22515915001991 - 2²⁶ = 22515847893127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22515915051991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11257957500995 + 11257957500996.

It is an arithmetic number, because the mean of its divisors is an integer number (11257957500996).

Almost surely, 2^{22515915001991} is an apocalyptic number.

22515915001991 is a deficient number, since it is larger than the sum of its proper divisors (1).

22515915001991 is an equidigital number, since it uses as much as digits as its factorization.

22515915001991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 364500, while the sum is 50.

The spelling of 22515915001991 in words is "twenty-two trillion, five hundred fifteen billion, nine hundred fifteen million, one thousand, nine hundred ninety-one".