2565521406 has 24 divisors (see below), whose sum is σ = 6352719984. Its totient is φ = 733006080.

The previous prime is 2565521393. The next prime is 2565521449. The reversal of 2565521406 is 6041255652.

2565521406 is a `hidden beast` number, since 2 + 565 + 52 + 1 + 40 + 6 = 666.

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, 10180515 + ... + 10180766.

It is an arithmetic number, because the mean of its divisors is an integer number (264696666).

Almost surely, 2^2565521406 is an apocalyptic number.

2565521406 is an abundant number, since it is smaller than the sum of its proper divisors (3787198578).

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

2565521406 is a wasteful number, since it uses less digits than its factorization.

2565521406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20361296 (or 20361293 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 36.

The square root of 2565521406 is about 50650.9763578157. The cubic root of 2565521406 is about 1368.9635377359.

The spelling of 2565521406 in words is "two billion, five hundred sixty-five million, five hundred twenty-one thousand, four hundred six".