66394251 has 48 divisors (see below), whose sum is σ = 120556800. Its totient is φ = 34205760.

The previous prime is 66394241. The next prime is 66394271. The reversal of 66394251 is 15249366.

It is a happy number.

It is not a de Polignac number, because 66394251 - 2²³ = 58005643 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66394241) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 102936 + ... + 103578.

It is an arithmetic number, because the mean of its divisors is an integer number (2511600).

Almost surely, 2^66394251 is an apocalyptic number.

66394251 is a deficient number, since it is larger than the sum of its proper divisors (54162549).

66394251 is a wasteful number, since it uses less digits than its factorization.

66394251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816 (or 813 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 66394251 is about 8148.2667482109. The cubic root of 66394251 is about 404.9270833520.

The spelling of 66394251 in words is "sixty-six million, three hundred ninety-four thousand, two hundred fifty-one".