1661731928 has 8 divisors (see below), whose sum is σ = 3115747380. Its totient is φ = 830865960.

The previous prime is 1661731919. The next prime is 1661731937. The reversal of 1661731928 is 8291371661.

It is an interprime number because it is at equal distance from previous prime (1661731919) and next prime (1661731937).

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×1661731928² = 5522706001069194368, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103858238 + ... + 103858253.

Almost surely, 2^1661731928 is an apocalyptic number.

It is an amenable number.

1661731928 is a deficient number, since it is larger than the sum of its proper divisors (1454015452).

1661731928 is a wasteful number, since it uses less digits than its factorization.

1661731928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207716497 (or 207716493 counting only the distinct ones).

The product of its digits is 108864, while the sum is 44.

The square root of 1661731928 is about 40764.3462844678. The cubic root of 1661731928 is about 1184.4597887823.

The spelling of 1661731928 in words is "one billion, six hundred sixty-one million, seven hundred thirty-one thousand, nine hundred twenty-eight".