121905728 has 42 divisors (see below), whose sum is σ = 281408886. Its totient is φ = 52243968.

The previous prime is 121905697. The next prime is 121905737. The reversal of 121905728 is 827509121.

It can be written as a sum of positive squares in only one way, i.e., 121705024 + 200704 = 11032^2 + 448^2 .

It is a super-2 number, since 2×121905728² = 29722013038419968, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 16301 + ... + 22572.

Almost surely, 2^121905728 is an apocalyptic number.

It is an amenable number.

121905728 is an abundant number, since it is smaller than the sum of its proper divisors (159503158).

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

121905728 is an equidigital number, since it uses as much as digits as its factorization.

121905728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38899 (or 38882 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 35.

The square root of 121905728 is about 11041.0926995475. The cubic root of 121905728 is about 495.8397852294.

The spelling of 121905728 in words is "one hundred twenty-one million, nine hundred five thousand, seven hundred twenty-eight".