1625642644 has 6 divisors (see below), whose sum is σ = 2844874634. Its totient is φ = 812821320.

The previous prime is 1625642633. The next prime is 1625642651. The reversal of 1625642644 is 4462465261.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1584836100 + 40806544 = 39810^2 + 6388^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1625642597 and 1625642606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 203205327 + ... + 203205334.

Almost surely, 2^1625642644 is an apocalyptic number.

It is an amenable number.

1625642644 is a deficient number, since it is larger than the sum of its proper divisors (1219231990).

1625642644 is a wasteful number, since it uses less digits than its factorization.

1625642644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406410665 (or 406410663 counting only the distinct ones).

The product of its digits is 276480, while the sum is 40.

The square root of 1625642644 is about 40319.2589713650. The cubic root of 1625642644 is about 1175.8223050888.

The spelling of 1625642644 in words is "one billion, six hundred twenty-five million, six hundred forty-two thousand, six hundred forty-four".