2521021666 has 16 divisors (see below), whose sum is σ = 3819239424. Its totient is φ = 1247990944.

The previous prime is 2521021627. The next prime is 2521021703. The reversal of 2521021666 is 6661201252.

2521021666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 92931 + ... + 116953.

It is an arithmetic number, because the mean of its divisors is an integer number (238702464).

Almost surely, 2^2521021666 is an apocalyptic number.

2521021666 is a deficient number, since it is larger than the sum of its proper divisors (1298217758).

2521021666 is a wasteful number, since it uses less digits than its factorization.

2521021666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24545.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 2521021666 is about 50209.7765977902. The cubic root of 2521021666 is about 1361.0023007132.

The spelling of 2521021666 in words is "two billion, five hundred twenty-one million, twenty-one thousand, six hundred sixty-six".