66700521 has 12 divisors (see below), whose sum is σ = 96561972. Its totient is φ = 44366976.

The previous prime is 66700519. The next prime is 66700523. The reversal of 66700521 is 12500766.

It is an interprime number because it is at equal distance from previous prime (66700519) and next prime (66700523).

It can be written as a sum of positive squares in 2 ways, for example, as 55711296 + 10989225 = 7464^2 + 3315^2 .

It is not a de Polignac number, because 66700521 - 2¹ = 66700519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66700523) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3996 + ... + 12221.

It is an arithmetic number, because the mean of its divisors is an integer number (8046831).

Almost surely, 2^66700521 is an apocalyptic number.

It is an amenable number.

66700521 is a deficient number, since it is larger than the sum of its proper divisors (29861451).

66700521 is a wasteful number, since it uses less digits than its factorization.

66700521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16680 (or 16677 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 66700521 is about 8167.0386922066. The cubic root of 66700521 is about 405.5487577212.

The spelling of 66700521 in words is "sixty-six million, seven hundred thousand, five hundred twenty-one".