66402557 has 8 divisors (see below), whose sum is σ = 71673336. Its totient is φ = 61155072.

The previous prime is 66402533. The next prime is 66402559. The reversal of 66402557 is 75520466.

It can be written as a sum of positive squares in 4 ways, for example, as 22033636 + 44368921 = 4694^2 + 6661^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66402557 - 2²⁴ = 49625341 is a prime.

It is a super-2 number, since 2×66402557² = 8818599152276498, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66402559) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 353 + ... + 11529.

It is an arithmetic number, because the mean of its divisors is an integer number (8959167).

Almost surely, 2^66402557 is an apocalyptic number.

It is an amenable number.

66402557 is a deficient number, since it is larger than the sum of its proper divisors (5270779).

66402557 is a wasteful number, since it uses less digits than its factorization.

66402557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11647.

The product of its (nonzero) digits is 50400, while the sum is 35.

The square root of 66402557 is about 8148.7764112166. The cubic root of 66402557 is about 404.9439682683.

The spelling of 66402557 in words is "sixty-six million, four hundred two thousand, five hundred fifty-seven".