1581561625 has 16 divisors (see below), whose sum is σ = 2255760000. Its totient is φ = 1084498800.

The previous prime is 1581561589. The next prime is 1581561647. The reversal of 1581561625 is 5261651851.

It is not a de Polignac number, because 1581561625 - 2¹⁵ = 1581528857 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 902875 + ... + 904624.

It is an arithmetic number, because the mean of its divisors is an integer number (140985000).

Almost surely, 2^1581561625 is an apocalyptic number.

It is an amenable number.

1581561625 is a deficient number, since it is larger than the sum of its proper divisors (674198375).

1581561625 is an equidigital number, since it uses as much as digits as its factorization.

1581561625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1807521 (or 1807511 counting only the distinct ones).

The product of its digits is 72000, while the sum is 40.

The square root of 1581561625 is about 39768.8524476128. The cubic root of 1581561625 is about 1165.0968808157.

The spelling of 1581561625 in words is "one billion, five hundred eighty-one million, five hundred sixty-one thousand, six hundred twenty-five".