121997811 has 16 divisors (see below), whose sum is σ = 176520960. Its totient is φ = 74499360.

The previous prime is 121997807. The next prime is 121997857. The reversal of 121997811 is 118799121.

It is not a de Polignac number, because 121997811 - 2² = 121997807 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a self number, because there is not a number n which added to its sum of digits gives 121997811.

It is not an unprimeable number, because it can be changed into a prime (121997111) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6831 + ... + 17048.

It is an arithmetic number, because the mean of its divisors is an integer number (11032560).

Almost surely, 2^121997811 is an apocalyptic number.

121997811 is a deficient number, since it is larger than the sum of its proper divisors (54523149).

121997811 is a wasteful number, since it uses less digits than its factorization.

121997811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24026.

The product of its digits is 9072, while the sum is 39.

The square root of 121997811 is about 11045.2619253687. The cubic root of 121997811 is about 495.9646000468.

The spelling of 121997811 in words is "one hundred twenty-one million, nine hundred ninety-seven thousand, eight hundred eleven".