2557821021 has 48 divisors (see below), whose sum is σ = 4209500160. Its totient is φ = 1373591520.

The previous prime is 2557820971. The next prime is 2557821023. The reversal of 2557821021 is 1201287552.

It is not a de Polignac number, because 2557821021 - 2¹⁵ = 2557788253 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2557821023) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 351106 + ... + 358316.

It is an arithmetic number, because the mean of its divisors is an integer number (87697920).

Almost surely, 2^2557821021 is an apocalyptic number.

2557821021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2557821021 is a deficient number, since it is larger than the sum of its proper divisors (1651679139).

2557821021 is a wasteful number, since it uses less digits than its factorization.

2557821021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7374 (or 7367 counting only the distinct ones).

The product of its (nonzero) digits is 11200, while the sum is 33.

The square root of 2557821021 is about 50574.9050518140. The cubic root of 2557821021 is about 1367.5925219951.

The spelling of 2557821021 in words is "two billion, five hundred fifty-seven million, eight hundred twenty-one thousand, twenty-one".