172215394691 has 2 divisors, whose sum is σ = 172215394692. Its totient is φ = 172215394690.

The previous prime is 172215394621. The next prime is 172215394693. The reversal of 172215394691 is 196493512271.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 172215394691 - 2³⁴ = 155035525507 is a prime.

Together with 172215394693, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (172215394693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86107697345 + 86107697346.

It is an arithmetic number, because the mean of its divisors is an integer number (86107697346).

Almost surely, 2^172215394691 is an apocalyptic number.

172215394691 is a deficient number, since it is larger than the sum of its proper divisors (1).

172215394691 is an equidigital number, since it uses as much as digits as its factorization.

172215394691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 816480, while the sum is 50.

The spelling of 172215394691 in words is "one hundred seventy-two billion, two hundred fifteen million, three hundred ninety-four thousand, six hundred ninety-one".