1661731139 has 2 divisors, whose sum is σ = 1661731140. Its totient is φ = 1661731138.

The previous prime is 1661731121. The next prime is 1661731151. The reversal of 1661731139 is 9311371661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1661731139 - 2⁸ = 1661730883 is a prime.

It is a super-2 number, since 2×1661731139² = 5522700756644474642, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1661031139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830865569 + 830865570.

It is an arithmetic number, because the mean of its divisors is an integer number (830865570).

Almost surely, 2^1661731139 is an apocalyptic number.

1661731139 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661731139 is an equidigital number, since it uses as much as digits as its factorization.

1661731139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20412, while the sum is 38.

The square root of 1661731139 is about 40764.3366068921. The cubic root of 1661731139 is about 1184.4596013195.

The spelling of 1661731139 in words is "one billion, six hundred sixty-one million, seven hundred thirty-one thousand, one hundred thirty-nine".