66420031 has 4 divisors (see below), whose sum is σ = 66754000. Its totient is φ = 66086064.

The previous prime is 66420023. The next prime is 66420043. The reversal of 66420031 is 13002466.

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

It is a cyclic number.

It is not a de Polignac number, because 66420031 - 2³ = 66420023 is a prime.

It is a super-2 number, since 2×66420031² = 8823241036081922, 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 = 66419984 and 66420011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66420061) 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, 166686 + ... + 167083.

It is an arithmetic number, because the mean of its divisors is an integer number (16688500).

Almost surely, 2^66420031 is an apocalyptic number.

66420031 is a deficient number, since it is larger than the sum of its proper divisors (333969).

66420031 is a wasteful number, since it uses less digits than its factorization.

66420031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333968.

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 66420031 is about 8149.8485261997. The cubic root of 66420031 is about 404.9794858278.

Adding to 66420031 its reverse (13002466), we get a palindrome (79422497).

The spelling of 66420031 in words is "sixty-six million, four hundred twenty thousand, thirty-one".