2557920 has 72 divisors (see below), whose sum is σ = 8169336. Its totient is φ = 672768.

The previous prime is 2557909. The next prime is 2557931. The reversal of 2557920 is 297552.

2557920 = 150² + 151² + ... + 222².

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (2557909) and next prime (2557931).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35004 + ... + 35076.

It is an arithmetic number, because the mean of its divisors is an integer number (113463).

2^2557920 is an apocalyptic number.

2557920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2557920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4084668).

2557920 is an abundant number, since it is smaller than the sum of its proper divisors (5611416).

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

2557920 is an equidigital number, since it uses as much as digits as its factorization.

2557920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164 (or 83 counting only the distinct ones).

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

The square root of 2557920 is about 1599.3498679151. The cubic root of 2557920 is about 136.7610162165.

Multiplying 2557920 by its sum of digits (30), we get a square (76737600 = 8760²).

2557920 divided by its sum of digits (30) gives a square (85264 = 292²).

The spelling of 2557920 in words is "two million, five hundred fifty-seven thousand, nine hundred twenty".