1661715636 has 48 divisors (see below), whose sum is σ = 4521686400. Its totient is φ = 474774720.

The previous prime is 1661715611. The next prime is 1661715697. The reversal of 1661715636 is 6365171661.

It is a happy number.

It is a super-2 number, since 2×1661715636² = 5522597709853768992, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 197745 + ... + 205976.

It is an arithmetic number, because the mean of its divisors is an integer number (94201800).

Almost surely, 2^1661715636 is an apocalyptic number.

It is an amenable number.

1661715636 is an abundant number, since it is smaller than the sum of its proper divisors (2859970764).

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

1661715636 is a wasteful number, since it uses less digits than its factorization.

1661715636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 403749 (or 403733 counting only the distinct ones).

The product of its digits is 136080, while the sum is 42.

The square root of 1661715636 is about 40764.1464524893. The cubic root of 1661715636 is about 1184.4559178647.

The spelling of 1661715636 in words is "one billion, six hundred sixty-one million, seven hundred fifteen thousand, six hundred thirty-six".