55215231 has 8 divisors (see below), whose sum is σ = 73914624. Its totient is φ = 36663000.

The previous prime is 55215179. The next prime is 55215239. The reversal of 55215231 is 13251255.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 55215231 - 2²³ = 46826623 is a prime.

It is a super-2 number, since 2×55215231² = 6097443468766722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55215239) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35911 + ... + 37416.

It is an arithmetic number, because the mean of its divisors is an integer number (9239328).

Almost surely, 2^55215231 is an apocalyptic number.

55215231 is a deficient number, since it is larger than the sum of its proper divisors (18699393).

55215231 is a wasteful number, since it uses less digits than its factorization.

55215231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73581.

The product of its digits is 1500, while the sum is 24.

The square root of 55215231 is about 7430.6951895499. The cubic root of 55215231 is about 380.7906690354.

Adding to 55215231 its reverse (13251255), we get a palindrome (68466486).

The spelling of 55215231 in words is "fifty-five million, two hundred fifteen thousand, two hundred thirty-one".