121637657 has 4 divisors (see below), whose sum is σ = 121675620. Its totient is φ = 121599696.

The previous prime is 121637653. The next prime is 121637683. The reversal of 121637657 is 756736121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 58736896 + 62900761 = 7664^2 + 7931^2 .

It is a cyclic number.

It is not a de Polignac number, because 121637657 - 2² = 121637653 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 121637657.

It is not an unprimeable number, because it can be changed into a prime (121637651) 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, 13682 + ... + 20747.

It is an arithmetic number, because the mean of its divisors is an integer number (30418905).

Almost surely, 2^121637657 is an apocalyptic number.

It is an amenable number.

121637657 is a deficient number, since it is larger than the sum of its proper divisors (37963).

121637657 is an equidigital number, since it uses as much as digits as its factorization.

121637657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37962.

The product of its digits is 52920, while the sum is 38.

The square root of 121637657 is about 11028.9463231988. The cubic root of 121637657 is about 495.4760675187.

The spelling of 121637657 in words is "one hundred twenty-one million, six hundred thirty-seven thousand, six hundred fifty-seven".