1604900981 has 4 divisors (see below), whose sum is σ = 1606011552. Its totient is φ = 1603790412.

The previous prime is 1604900959. The next prime is 1604901017. The reversal of 1604900981 is 1890094061.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1890094061 = 139 ⋅13597799.

It is a cyclic number.

It is not a de Polignac number, because 1604900981 - 2²² = 1600706677 is a prime.

It is a super-2 number, since 2×1604900981² = 5151414317629524722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1604900081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 553115 + ... + 556008.

It is an arithmetic number, because the mean of its divisors is an integer number (401502888).

Almost surely, 2^1604900981 is an apocalyptic number.

It is an amenable number.

1604900981 is a deficient number, since it is larger than the sum of its proper divisors (1110571).

1604900981 is a wasteful number, since it uses less digits than its factorization.

1604900981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1110570.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 1604900981 is about 40061.2154209030. The cubic root of 1604900981 is about 1170.8000909677.

The spelling of 1604900981 in words is "one billion, six hundred four million, nine hundred thousand, nine hundred eighty-one".