66421257 has 16 divisors (see below), whose sum is σ = 101391360. Its totient is φ = 37888272.

The previous prime is 66421249. The next prime is 66421259. The reversal of 66421257 is 75212466.

It is not a de Polignac number, because 66421257 - 2³ = 66421249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66421259) 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, 11044 + ... + 15962.

It is an arithmetic number, because the mean of its divisors is an integer number (6336960).

Almost surely, 2^66421257 is an apocalyptic number.

It is an amenable number.

66421257 is a deficient number, since it is larger than the sum of its proper divisors (34970103).

66421257 is a wasteful number, since it uses less digits than its factorization.

66421257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5572.

The product of its digits is 20160, while the sum is 33.

The square root of 66421257 is about 8149.9237419745. The cubic root of 66421257 is about 404.9819775550.

The spelling of 66421257 in words is "sixty-six million, four hundred twenty-one thousand, two hundred fifty-seven".