1581638401 has 16 divisors (see below), whose sum is σ = 1997132544. Its totient is φ = 1220465664.

The previous prime is 1581638363. The next prime is 1581638417. The reversal of 1581638401 is 1048361851.

It is a cyclic number.

It is not a de Polignac number, because 1581638401 - 2¹⁹ = 1581114113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1581638431) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 286200 + ... + 291673.

It is an arithmetic number, because the mean of its divisors is an integer number (124820784).

Almost surely, 2^1581638401 is an apocalyptic number.

It is an amenable number.

1581638401 is a deficient number, since it is larger than the sum of its proper divisors (415494143).

1581638401 is a wasteful number, since it uses less digits than its factorization.

1581638401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 577920.

The product of its (nonzero) digits is 23040, while the sum is 37.

The square root of 1581638401 is about 39769.8177139398. The cubic root of 1581638401 is about 1165.1157334968.

The spelling of 1581638401 in words is "one billion, five hundred eighty-one million, six hundred thirty-eight thousand, four hundred one".