1604781 has 12 divisors (see below), whose sum is σ = 2375100. Its totient is φ = 1043520.

The previous prime is 1604753. The next prime is 1604809. The reversal of 1604781 is 1874061.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1604753) and next prime (1604809).

It can be written as a sum of positive squares in 2 ways, for example, as 54756 + 1550025 = 234^2 + 1245^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1604781 is a prime.

It is a super-2 number, since 2×1604781² = 5150644115922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1604711) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1806 + ... + 2543.

It is an arithmetic number, because the mean of its divisors is an integer number (197925).

2^1604781 is an apocalyptic number.

It is an amenable number.

1604781 is a deficient number, since it is larger than the sum of its proper divisors (770319).

1604781 is a wasteful number, since it uses less digits than its factorization.

1604781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4396 (or 4393 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 1604781 is about 1266.7995105777. The cubic root of 1604781 is about 117.0770914242.

The spelling of 1604781 in words is "one million, six hundred four thousand, seven hundred eighty-one".