1661812688 has 20 divisors (see below), whose sum is σ = 3222159840. Its totient is φ = 830287584.

The previous prime is 1661812687. The next prime is 1661812729. The reversal of 1661812688 is 8862181661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661812681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16118 + ... + 59861.

It is an arithmetic number, because the mean of its divisors is an integer number (161107992).

Almost surely, 2^1661812688 is an apocalyptic number.

It is an amenable number.

1661812688 is a deficient number, since it is larger than the sum of its proper divisors (1560347152).

1661812688 is a wasteful number, since it uses less digits than its factorization.

1661812688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77354 (or 77348 counting only the distinct ones).

The product of its digits is 221184, while the sum is 47.

The square root of 1661812688 is about 40765.3368439413. The cubic root of 1661812688 is about 1184.4789766793.

The spelling of 1661812688 in words is "one billion, six hundred sixty-one million, eight hundred twelve thousand, six hundred eighty-eight".