122156721 has 16 divisors (see below), whose sum is σ = 185865600. Its totient is φ = 79236144.

The previous prime is 122156717. The next prime is 122156767. The reversal of 122156721 is 127651221.

It is not a de Polignac number, because 122156721 - 2² = 122156717 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (122156711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60141 + ... + 62138.

It is an arithmetic number, because the mean of its divisors is an integer number (11616600).

Almost surely, 2^122156721 is an apocalyptic number.

It is an amenable number.

122156721 is a deficient number, since it is larger than the sum of its proper divisors (63708879).

122156721 is a wasteful number, since it uses less digits than its factorization.

122156721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122325 (or 122319 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 122156721 is about 11052.4531666051. The cubic root of 122156721 is about 496.1798485520.

The spelling of 122156721 in words is "one hundred twenty-two million, one hundred fifty-six thousand, seven hundred twenty-one".