55220915 has 4 divisors (see below), whose sum is σ = 66265104. Its totient is φ = 44176728.

The previous prime is 55220903. The next prime is 55220927. The reversal of 55220915 is 51902255.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 51902255 = 5 ⋅10380451.

It is an interprime number because it is at equal distance from previous prime (55220903) and next prime (55220927).

It is a cyclic number.

It is not a de Polignac number, because 55220915 - 2⁴ = 55220899 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5522087 + ... + 5522096.

It is an arithmetic number, because the mean of its divisors is an integer number (16566276).

Almost surely, 2^55220915 is an apocalyptic number.

55220915 is a deficient number, since it is larger than the sum of its proper divisors (11044189).

55220915 is a wasteful number, since it uses less digits than its factorization.

55220915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11044188.

The product of its (nonzero) digits is 4500, while the sum is 29.

The square root of 55220915 is about 7431.0776472864. The cubic root of 55220915 is about 380.8037351155.

The spelling of 55220915 in words is "fifty-five million, two hundred twenty thousand, nine hundred fifteen".