921240097691 has 4 divisors (see below), whose sum is σ = 921513384984. Its totient is φ = 920966810400.

The previous prime is 921240097669. The next prime is 921240097733. The reversal of 921240097691 is 196790042129.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 196790042129 = 83 ⋅2370964363.

It is a cyclic number.

It is not a de Polignac number, because 921240097691 - 2¹⁸ = 921239835547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (921240097621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 136638590 + ... + 136645331.

It is an arithmetic number, because the mean of its divisors is an integer number (230378346246).

Almost surely, 2^921240097691 is an apocalyptic number.

921240097691 is a deficient number, since it is larger than the sum of its proper divisors (273287293).

921240097691 is a wasteful number, since it uses less digits than its factorization.

921240097691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273287292.

The product of its (nonzero) digits is 489888, while the sum is 50.

The spelling of 921240097691 in words is "nine hundred twenty-one billion, two hundred forty million, ninety-seven thousand, six hundred ninety-one".