1661761764 has 96 divisors (see below), whose sum is σ = 4912669440. Its totient is φ = 481227264.

The previous prime is 1661761733. The next prime is 1661761807. The reversal of 1661761764 is 4671671661.

1661761764 is a `hidden beast` number, since 16 + 6 + 17 + 617 + 6 + 4 = 666.

It is a super-2 number, since 2×1661761764² = 5522904320584783392, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10944 + ... + 58679.

It is an arithmetic number, because the mean of its divisors is an integer number (51173640).

Almost surely, 2^1661761764 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1661761764, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2456334720).

1661761764 is an abundant number, since it is smaller than the sum of its proper divisors (3250907676).

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

1661761764 is a wasteful number, since it uses less digits than its factorization.

1661761764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69666 (or 69658 counting only the distinct ones).

The product of its digits is 254016, while the sum is 45.

The square root of 1661761764 is about 40764.7122398773. The cubic root of 1661761764 is about 1184.4668776375.

The spelling of 1661761764 in words is "one billion, six hundred sixty-one million, seven hundred sixty-one thousand, seven hundred sixty-four".