121561640 has 16 divisors (see below), whose sum is σ = 273513780. Its totient is φ = 48624640.

The previous prime is 121561637. The next prime is 121561669. The reversal of 121561640 is 46165121.

It can be written as a sum of positive squares in 2 ways, for example, as 115906756 + 5654884 = 10766^2 + 2378^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1519481 + ... + 1519560.

Almost surely, 2^121561640 is an apocalyptic number.

121561640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121561640 is an abundant number, since it is smaller than the sum of its proper divisors (151952140).

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

121561640 is a wasteful number, since it uses less digits than its factorization.

121561640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3039052 (or 3039048 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 121561640 is about 11025.4995351685. The cubic root of 121561640 is about 495.3728307031.

The spelling of 121561640 in words is "one hundred twenty-one million, five hundred sixty-one thousand, six hundred forty".