1604691 has 20 divisors (see below), whose sum is σ = 2616504. Its totient is φ = 972000.

The previous prime is 1604651. The next prime is 1604711. The reversal of 1604691 is 1964061.

It is not a de Polignac number, because 1604691 - 2⁹ = 1604179 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1604611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 10 + ... + 1791.

2^1604691 is an apocalyptic number.

1604691 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1604691 is a deficient number, since it is larger than the sum of its proper divisors (1011813).

1604691 is a wasteful number, since it uses less digits than its factorization.

1604691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1824 (or 1815 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 1604691 is about 1266.7639874894. The cubic root of 1604691 is about 117.0749027278.

It can be divided in two parts, 160 and 4691, that added together give a triangular number (4851 = T₉₈).

The spelling of 1604691 in words is "one million, six hundred four thousand, six hundred ninety-one".