1625684721 has 8 divisors (see below), whose sum is σ = 2295084384. Its totient is φ = 1020037440.

The previous prime is 1625684719. The next prime is 1625684747. The reversal of 1625684721 is 1274865261.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1625684721 - 2¹ = 1625684719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1625684701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15938035 + ... + 15938136.

It is an arithmetic number, because the mean of its divisors is an integer number (286885548).

Almost surely, 2^1625684721 is an apocalyptic number.

It is an amenable number.

1625684721 is a deficient number, since it is larger than the sum of its proper divisors (669399663).

1625684721 is a wasteful number, since it uses less digits than its factorization.

1625684721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31876191.

The product of its digits is 161280, while the sum is 42.

The square root of 1625684721 is about 40319.7807657730. The cubic root of 1625684721 is about 1175.8324497226.

The spelling of 1625684721 in words is "one billion, six hundred twenty-five million, six hundred eighty-four thousand, seven hundred twenty-one".