1661860656 has 60 divisors (see below), whose sum is σ = 4694411592. Its totient is φ = 548771328.

The previous prime is 1661860649. The next prime is 1661860657. The reversal of 1661860656 is 6560681661.

It is not an unprimeable number, because it can be changed into a prime (1661860657) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38521 + ... + 69336.

Almost surely, 2^1661860656 is an apocalyptic number.

1661860656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1661860656 is an abundant number, since it is smaller than the sum of its proper divisors (3032550936).

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

1661860656 is a wasteful number, since it uses less digits than its factorization.

1661860656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107978 (or 107969 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The square root of 1661860656 is about 40765.9251826817. The cubic root of 1661860656 is about 1184.4903731785.

The spelling of 1661860656 in words is "one billion, six hundred sixty-one million, eight hundred sixty thousand, six hundred fifty-six".