55720290 has 16 divisors (see below), whose sum is σ = 133728768. Its totient is φ = 14858736.

The previous prime is 55720289. The next prime is 55720297. The reversal of 55720290 is 9202755.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 1857343 = 55720290 / (5 + 5 + 7 + 2 + 0 + 2 + 9 + 0).

It is not an unprimeable number, because it can be changed into a prime (55720297) 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, 928642 + ... + 928701.

It is an arithmetic number, because the mean of its divisors is an integer number (8358048).

Almost surely, 2^55720290 is an apocalyptic number.

55720290 is an abundant number, since it is smaller than the sum of its proper divisors (78008478).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

55720290 is a wasteful number, since it uses less digits than its factorization.

55720290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1857353.

The product of its (nonzero) digits is 6300, while the sum is 30.

The square root of 55720290 is about 7464.6024676469. The cubic root of 55720290 is about 381.9481897516.

The spelling of 55720290 in words is "fifty-five million, seven hundred twenty thousand, two hundred ninety".