1631423721 has 32 divisors (see below), whose sum is σ = 2295613440. Its totient is φ = 1029329856.

The previous prime is 1631423719. The next prime is 1631423723. The reversal of 1631423721 is 1273241361.

It is a happy number.

1631423721 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (1631423719) and next prime (1631423723).

It is not a de Polignac number, because 1631423721 - 2¹ = 1631423719 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1631423723) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 932970 + ... + 934716.

It is an arithmetic number, because the mean of its divisors is an integer number (71737920).

Almost surely, 2^1631423721 is an apocalyptic number.

It is an amenable number.

1631423721 is a deficient number, since it is larger than the sum of its proper divisors (664189719).

1631423721 is a wasteful number, since it uses less digits than its factorization.

1631423721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2013.

The product of its digits is 6048, while the sum is 30.

The square root of 1631423721 is about 40390.8866082437. The cubic root of 1631423721 is about 1177.2144678452.

The spelling of 1631423721 in words is "one billion, six hundred thirty-one million, four hundred twenty-three thousand, seven hundred twenty-one".