1661689137 has 24 divisors (see below), whose sum is σ = 2343082944. Its totient is φ = 1047357216.

The previous prime is 1661689121. The next prime is 1661689147. The reversal of 1661689137 is 7319861661.

It is not a de Polignac number, because 1661689137 - 2⁴ = 1661689121 is a prime.

It is a super-2 number, since 2×1661689137² = 5522421576047609538, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661689147) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 662628 + ... + 665130.

It is an arithmetic number, because the mean of its divisors is an integer number (97628456).

Almost surely, 2^1661689137 is an apocalyptic number.

It is an amenable number.

1661689137 is a deficient number, since it is larger than the sum of its proper divisors (681393807).

1661689137 is a wasteful number, since it uses less digits than its factorization.

1661689137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3157 (or 3138 counting only the distinct ones).

The product of its digits is 326592, while the sum is 48.

The square root of 1661689137 is about 40763.8214229235. The cubic root of 1661689137 is about 1184.4496217485.

The spelling of 1661689137 in words is "one billion, six hundred sixty-one million, six hundred eighty-nine thousand, one hundred thirty-seven".