1661901964 has 12 divisors (see below), whose sum is σ = 2913649144. Its totient is φ = 829430784.

The previous prime is 1661901959. The next prime is 1661901977. The reversal of 1661901964 is 4691091661.

It is a self number, because there is not a number n which added to its sum of digits gives 1661901964.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 377589 + ... + 381964.

Almost surely, 2^1661901964 is an apocalyptic number.

It is an amenable number.

1661901964 is a deficient number, since it is larger than the sum of its proper divisors (1251747180).

1661901964 is a wasteful number, since it uses less digits than its factorization.

1661901964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 760104 (or 760102 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 43.

The square root of 1661901964 is about 40766.4318281598. The cubic root of 1661901964 is about 1184.5001871828.

The spelling of 1661901964 in words is "one billion, six hundred sixty-one million, nine hundred one thousand, nine hundred sixty-four".