66815943 has 16 divisors (see below), whose sum is σ = 95963136. Its totient is φ = 41231520.

The previous prime is 66815941. The next prime is 66815953. The reversal of 66815943 is 34951866.

It is not a de Polignac number, because 66815943 - 2¹ = 66815941 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66815895 and 66815904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66815941) 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, 13480 + ... + 17757.

It is an arithmetic number, because the mean of its divisors is an integer number (5997696).

Almost surely, 2^66815943 is an apocalyptic number.

66815943 is a deficient number, since it is larger than the sum of its proper divisors (29147193).

66815943 is a wasteful number, since it uses less digits than its factorization.

66815943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31294.

The product of its digits is 155520, while the sum is 42.

The square root of 66815943 is about 8174.1019690239. The cubic root of 66815943 is about 405.7825503692.

The spelling of 66815943 in words is "sixty-six million, eight hundred fifteen thousand, nine hundred forty-three".