13173921 has 10 divisors (see below), whose sum is σ = 19679682. Its totient is φ = 8782560.

The previous prime is 13173911. The next prime is 13173931. The reversal of 13173921 is 12937131.

It is an interprime number because it is at equal distance from previous prime (13173911) and next prime (13173931).

It can be written as a sum of positive squares in only one way, i.e., 7485696 + 5688225 = 2736^2 + 2385^2 .

It is not a de Polignac number, because 13173921 - 2⁵ = 13173889 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (13173911) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 81240 + ... + 81401.

Almost surely, 2^13173921 is an apocalyptic number.

It is an amenable number.

13173921 is a deficient number, since it is larger than the sum of its proper divisors (6505761).

13173921 is an equidigital number, since it uses as much as digits as its factorization.

13173921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162653 (or 162644 counting only the distinct ones).

The product of its digits is 1134, while the sum is 27.

The square root of 13173921 is about 3629.5896462272. The cubic root of 13173921 is about 236.1774077801.

The spelling of 13173921 in words is "thirteen million, one hundred seventy-three thousand, nine hundred twenty-one".