1561634880 has 112 divisors (see below), whose sum is σ = 5339632704. Its totient is φ = 384399360.

The previous prime is 1561634863. The next prime is 1561634897. The reversal of 1561634880 is 884361651.

It is an interprime number because it is at equal distance from previous prime (1561634863) and next prime (1561634897).

It is a super-3 number, since 3×1561634880³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50086 + ... + 75045.

It is an arithmetic number, because the mean of its divisors is an integer number (47675292).

Almost surely, 2^1561634880 is an apocalyptic number.

1561634880 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1561634880 is an abundant number, since it is smaller than the sum of its proper divisors (3777997824).

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

1561634880 is a wasteful number, since it uses less digits than its factorization.

1561634880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125164 (or 125154 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 42.

The square root of 1561634880 is about 39517.5262383667. The cubic root of 1561634880 is about 1160.1830071946.

The spelling of 1561634880 in words is "one billion, five hundred sixty-one million, six hundred thirty-four thousand, eight hundred eighty".