1666747731 has 16 divisors (see below), whose sum is σ = 2437763328. Its totient is φ = 1004565600.

The previous prime is 1666747723. The next prime is 1666747741. The reversal of 1666747731 is 1377476661.

It is not a de Polignac number, because 1666747731 - 2³ = 1666747723 is a prime.

It is a super-2 number, since 2×1666747731² = 5556095997587296722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1666747721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 133551 + ... + 145496.

It is an arithmetic number, because the mean of its divisors is an integer number (152360208).

Almost surely, 2^1666747731 is an apocalyptic number.

1666747731 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1666747731 is a deficient number, since it is larger than the sum of its proper divisors (771015597).

1666747731 is a wasteful number, since it uses less digits than its factorization.

1666747731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279242.

The product of its digits is 889056, while the sum is 48.

The square root of 1666747731 is about 40825.8218655791. The cubic root of 1666747731 is about 1185.6503236640.

The spelling of 1666747731 in words is "one billion, six hundred sixty-six million, seven hundred forty-seven thousand, seven hundred thirty-one".