121631557 has 4 divisors (see below), whose sum is σ = 122437216. Its totient is φ = 120825900.

The previous prime is 121631527. The next prime is 121631579. The reversal of 121631557 is 755136121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121631557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121631527) 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, 402603 + ... + 402904.

It is an arithmetic number, because the mean of its divisors is an integer number (30609304).

Almost surely, 2^121631557 is an apocalyptic number.

It is an amenable number.

121631557 is a deficient number, since it is larger than the sum of its proper divisors (805659).

121631557 is an equidigital number, since it uses as much as digits as its factorization.

121631557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 805658.

The product of its digits is 6300, while the sum is 31.

The square root of 121631557 is about 11028.6697747280. The cubic root of 121631557 is about 495.4677848464.

Adding to 121631557 its reverse (755136121), we get a palindrome (876767678).

The spelling of 121631557 in words is "one hundred twenty-one million, six hundred thirty-one thousand, five hundred fifty-seven".