1661671755 has 48 divisors (see below), whose sum is σ = 2919533760. Its totient is φ = 874209024.

The previous prime is 1661671721. The next prime is 1661671807. The reversal of 1661671755 is 5571761661.

1661671755 is a `hidden beast` number, since 16 + 616 + 7 + 17 + 5 + 5 = 666.

It is not a de Polignac number, because 1661671755 - 2²¹ = 1659574603 is a prime.

It is a super-2 number, since 2×1661671755² = 5522306042729560050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 1661671755.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1358074 + ... + 1359296.

It is an arithmetic number, because the mean of its divisors is an integer number (60823620).

Almost surely, 2^1661671755 is an apocalyptic number.

1661671755 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1661671755 is a deficient number, since it is larger than the sum of its proper divisors (1257862005).

1661671755 is a wasteful number, since it uses less digits than its factorization.

1661671755 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1620 (or 1617 counting only the distinct ones).

The product of its digits is 264600, while the sum is 45.

The square root of 1661671755 is about 40763.6082186060. The cubic root of 1661671755 is about 1184.4454917793.

The spelling of 1661671755 in words is "one billion, six hundred sixty-one million, six hundred seventy-one thousand, seven hundred fifty-five".