121656815 has 8 divisors (see below), whose sum is σ = 166843680. Its totient is φ = 83421792.

The previous prime is 121656809. The next prime is 121656833. The reversal of 121656815 is 518656121.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 121656815 - 2⁶ = 121656751 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35), and also a Moran number because the ratio is a prime number: 3475909 = 121656815 / (1 + 2 + 1 + 6 + 5 + 6 + 8 + 1 + 5).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1737920 + ... + 1737989.

It is an arithmetic number, because the mean of its divisors is an integer number (20855460).

Almost surely, 2^121656815 is an apocalyptic number.

121656815 is a deficient number, since it is larger than the sum of its proper divisors (45186865).

121656815 is an equidigital number, since it uses as much as digits as its factorization.

121656815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3475921.

The product of its digits is 14400, while the sum is 35.

The square root of 121656815 is about 11029.8148216550. The cubic root of 121656815 is about 495.5020787404.

The spelling of 121656815 in words is "one hundred twenty-one million, six hundred fifty-six thousand, eight hundred fifteen".