121561560 has 160 divisors (see below), whose sum is σ = 432812160. Its totient is φ = 30495744.

The previous prime is 121561549. The next prime is 121561579. The reversal of 121561560 is 65165121.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 53977 + ... + 56183.

It is an arithmetic number, because the mean of its divisors is an integer number (2705076).

Almost surely, 2^121561560 is an apocalyptic number.

121561560 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121561560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (216406080).

121561560 is an abundant number, since it is smaller than the sum of its proper divisors (311250600).

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

121561560 is a wasteful number, since it uses less digits than its factorization.

121561560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2247 (or 2234 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 121561560 is about 11025.4959072143. The cubic root of 121561560 is about 495.3727220345.

The spelling of 121561560 in words is "one hundred twenty-one million, five hundred sixty-one thousand, five hundred sixty".