55215331 has 2 divisors, whose sum is σ = 55215332. Its totient is φ = 55215330.

The previous prime is 55215323. The next prime is 55215343. The reversal of 55215331 is 13351255.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 55215331 - 2³ = 55215323 is a prime.

It is a super-2 number, since 2×55215331² = 6097465554879122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 55215296 and 55215305.

It is not a weakly prime, because it can be changed into another prime (55215361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27607665 + 27607666.

It is an arithmetic number, because the mean of its divisors is an integer number (27607666).

Almost surely, 2^55215331 is an apocalyptic number.

55215331 is a deficient number, since it is larger than the sum of its proper divisors (1).

55215331 is an equidigital number, since it uses as much as digits as its factorization.

55215331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2250, while the sum is 25.

The square root of 55215331 is about 7430.7019183924. The cubic root of 55215331 is about 380.7908989179.

Adding to 55215331 its reverse (13351255), we get a palindrome (68566586).

The spelling of 55215331 in words is "fifty-five million, two hundred fifteen thousand, three hundred thirty-one".