121531657 has 32 divisors (see below), whose sum is σ = 147813120. Its totient is φ = 98703360.

The previous prime is 121531649. The next prime is 121531661. The reversal of 121531657 is 756135121.

It is not a de Polignac number, because 121531657 - 2³ = 121531649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121531607) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 432357 + ... + 432637.

It is an arithmetic number, because the mean of its divisors is an integer number (4619160).

Almost surely, 2^121531657 is an apocalyptic number.

121531657 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

121531657 is a deficient number, since it is larger than the sum of its proper divisors (26281463).

121531657 is a wasteful number, since it uses less digits than its factorization.

121531657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 433.

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

The square root of 121531657 is about 11024.1397396804. The cubic root of 121531657 is about 495.3320996938.

Adding to 121531657 its reverse (756135121), we get a palindrome (877666778).

The spelling of 121531657 in words is "one hundred twenty-one million, five hundred thirty-one thousand, six hundred fifty-seven".