917920121 has 4 divisors (see below), whose sum is σ = 922579812. Its totient is φ = 913260432.

The previous prime is 917920111. The next prime is 917920123. The reversal of 917920121 is 121029719.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 737394025 + 180526096 = 27155^2 + 13436^2 .

It is a cyclic number.

It is not a de Polignac number, because 917920121 - 2⁶ = 917920057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (917920123) 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, 2329550 + ... + 2329943.

It is an arithmetic number, because the mean of its divisors is an integer number (230644953).

Almost surely, 2^917920121 is an apocalyptic number.

It is an amenable number.

917920121 is a deficient number, since it is larger than the sum of its proper divisors (4659691).

917920121 is a wasteful number, since it uses less digits than its factorization.

917920121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4659690.

The product of its (nonzero) digits is 2268, while the sum is 32.

The square root of 917920121 is about 30297.1965864830. The cubic root of 917920121 is about 971.8553503552.

The spelling of 917920121 in words is "nine hundred seventeen million, nine hundred twenty thousand, one hundred twenty-one".