66121939 has 4 divisors (see below), whose sum is σ = 71208256. Its totient is φ = 61035624.

The previous prime is 66121933. The next prime is 66121961. The reversal of 66121939 is 93912166.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 66121939 - 2³ = 66121931 is a prime.

It is a super-2 number, since 2×66121939² = 8744221634239442, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66121898 and 66121907.

It is not an unprimeable number, because it can be changed into a prime (66121931) 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, 2543139 + ... + 2543164.

It is an arithmetic number, because the mean of its divisors is an integer number (17802064).

Almost surely, 2^66121939 is an apocalyptic number.

66121939 is a deficient number, since it is larger than the sum of its proper divisors (5086317).

66121939 is a wasteful number, since it uses less digits than its factorization.

66121939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5086316.

The product of its digits is 17496, while the sum is 37.

The square root of 66121939 is about 8131.5397680882. The cubic root of 66121939 is about 404.3727301404.

The spelling of 66121939 in words is "sixty-six million, one hundred twenty-one thousand, nine hundred thirty-nine".