1661500040 has 16 divisors (see below), whose sum is σ = 3738375180. Its totient is φ = 664600000.

The previous prime is 1661500033. The next prime is 1661500051. The reversal of 1661500040 is 400051661.

It can be written as a sum of positive squares in 2 ways, for example, as 1660888516 + 611524 = 40754^2 + 782^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1661499979 and 1661500015.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20768711 + ... + 20768790.

Almost surely, 2^1661500040 is an apocalyptic number.

1661500040 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1661500040 is an abundant number, since it is smaller than the sum of its proper divisors (2076875140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1661500040 is a wasteful number, since it uses less digits than its factorization.

1661500040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41537512 (or 41537508 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 1661500040 is about 40761.5019350367. The cubic root of 1661500040 is about 1184.4046906878.

The spelling of 1661500040 in words is "one billion, six hundred sixty-one million, five hundred thousand, forty".