55217397 has 4 divisors (see below), whose sum is σ = 73623200. Its totient is φ = 36811596.

The previous prime is 55217389. The next prime is 55217443. The reversal of 55217397 is 79371255.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 55217397 - 2³ = 55217389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55217317) 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, 9202897 + ... + 9202902.

It is an arithmetic number, because the mean of its divisors is an integer number (18405800).

Almost surely, 2^55217397 is an apocalyptic number.

It is an amenable number.

55217397 is a deficient number, since it is larger than the sum of its proper divisors (18405803).

55217397 is a wasteful number, since it uses less digits than its factorization.

55217397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18405802.

The product of its digits is 66150, while the sum is 39.

The square root of 55217397 is about 7430.8409349144. The cubic root of 55217397 is about 380.7956482280.

The spelling of 55217397 in words is "fifty-five million, two hundred seventeen thousand, three hundred ninety-seven".