1661644748 has 12 divisors (see below), whose sum is σ = 2908974600. Its totient is φ = 830509152.

The previous prime is 1661644739. The next prime is 1661644757. The reversal of 1661644748 is 8474461661.

It is an interprime number because it is at equal distance from previous prime (1661644739) and next prime (1661644757).

It is a super-2 number, since 2×1661644748² = 5522126537111967008, which contains 22 as substring.

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, 66161 + ... + 87752.

It is an arithmetic number, because the mean of its divisors is an integer number (242414550).

Almost surely, 2^1661644748 is an apocalyptic number.

It is an amenable number.

1661644748 is a deficient number, since it is larger than the sum of its proper divisors (1247329852).

1661644748 is a wasteful number, since it uses less digits than its factorization.

1661644748 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156616 (or 156614 counting only the distinct ones).

The product of its digits is 774144, while the sum is 47.

The square root of 1661644748 is about 40763.2769536503. The cubic root of 1661644748 is about 1184.4390748496.

The spelling of 1661644748 in words is "one billion, six hundred sixty-one million, six hundred forty-four thousand, seven hundred forty-eight".