1625384721 has 12 divisors (see below), whose sum is σ = 2244490352. Its totient is φ = 1046223024.

The previous prime is 1625384707. The next prime is 1625384731. The reversal of 1625384721 is 1274835261.

It is not a de Polignac number, because 1625384721 - 2¹¹ = 1625382673 is a prime.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1625384721.

It is not an unprimeable number, because it can be changed into a prime (1625384701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 319591 + ... + 324636.

Almost surely, 2^1625384721 is an apocalyptic number.

It is an amenable number.

1625384721 is a deficient number, since it is larger than the sum of its proper divisors (619105631).

1625384721 is an equidigital number, since it uses as much as digits as its factorization.

1625384721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 644288 (or 644259 counting only the distinct ones).

The product of its digits is 80640, while the sum is 39.

The square root of 1625384721 is about 40316.0603358017. The cubic root of 1625384721 is about 1175.7601168299.

The spelling of 1625384721 in words is "one billion, six hundred twenty-five million, three hundred eighty-four thousand, seven hundred twenty-one".