1604939891 has 16 divisors (see below), whose sum is σ = 1638667008. Its totient is φ = 1571724000.

The previous prime is 1604939887. The next prime is 1604939911. The reversal of 1604939891 is 1989394061.

It is a cyclic number.

It is not a de Polignac number, because 1604939891 - 2² = 1604939887 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1604939801) 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, 4848596 + ... + 4848926.

It is an arithmetic number, because the mean of its divisors is an integer number (102416688).

Almost surely, 2^1604939891 is an apocalyptic number.

1604939891 is a deficient number, since it is larger than the sum of its proper divisors (33727117).

1604939891 is a wasteful number, since it uses less digits than its factorization.

1604939891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 842.

The product of its (nonzero) digits is 419904, while the sum is 50.

The square root of 1604939891 is about 40061.7010497557. The cubic root of 1604939891 is about 1170.8095527068.

The spelling of 1604939891 in words is "one billion, six hundred four million, nine hundred thirty-nine thousand, eight hundred ninety-one".