121525681 has 4 divisors (see below), whose sum is σ = 124489764. Its totient is φ = 118561600.

The previous prime is 121525667. The next prime is 121525699. The reversal of 121525681 is 186525121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 186525121 = 233 ⋅800537.

It can be written as a sum of positive squares in 2 ways, for example, as 33466225 + 88059456 = 5785^2 + 9384^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121525681 is a prime.

It is a super-2 number, since 2×121525681² = 29536982285027522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121525981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1481980 + ... + 1482061.

It is an arithmetic number, because the mean of its divisors is an integer number (31122441).

Almost surely, 2^121525681 is an apocalyptic number.

It is an amenable number.

121525681 is a deficient number, since it is larger than the sum of its proper divisors (2964083).

121525681 is an equidigital number, since it uses as much as digits as its factorization.

121525681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2964082.

The product of its digits is 4800, while the sum is 31.

The square root of 121525681 is about 11023.8686947913. The cubic root of 121525681 is about 495.3239806758.

It can be divided in two parts, 1215 and 25681, that added together give a square (26896 = 164²).

The spelling of 121525681 in words is "one hundred twenty-one million, five hundred twenty-five thousand, six hundred eighty-one".