66891029 has 4 divisors (see below), whose sum is σ = 67080876. Its totient is φ = 66701184.

The previous prime is 66890983. The next prime is 66891043. The reversal of 66891029 is 92019866.

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

It can be written as a sum of positive squares in 2 ways, for example, as 30228004 + 36663025 = 5498^2 + 6055^2 .

It is a cyclic number.

It is not a de Polignac number, because 66891029 - 2²⁴ = 50113813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66890029) 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, 94394 + ... + 95099.

It is an arithmetic number, because the mean of its divisors is an integer number (16770219).

Almost surely, 2^66891029 is an apocalyptic number.

It is an amenable number.

66891029 is a deficient number, since it is larger than the sum of its proper divisors (189847).

66891029 is a wasteful number, since it uses less digits than its factorization.

66891029 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189846.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 66891029 is about 8178.6935998361. The cubic root of 66891029 is about 405.9344960529.

The spelling of 66891029 in words is "sixty-six million, eight hundred ninety-one thousand, twenty-nine".