66640537 has 2 divisors, whose sum is σ = 66640538. Its totient is φ = 66640536.

The previous prime is 66640531. The next prime is 66640571. The reversal of 66640537 is 73504666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 52359696 + 14280841 = 7236^2 + 3779^2 .

It is a cyclic number.

It is not a de Polignac number, because 66640537 - 2¹⁵ = 66607769 is a prime.

It is a super-2 number, since 2×66640537² = 8881922343296738, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66640496 and 66640505.

It is not a weakly prime, because it can be changed into another prime (66640531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33320268 + 33320269.

It is an arithmetic number, because the mean of its divisors is an integer number (33320269).

Almost surely, 2^66640537 is an apocalyptic number.

It is an amenable number.

66640537 is a deficient number, since it is larger than the sum of its proper divisors (1).

66640537 is an equidigital number, since it uses as much as digits as its factorization.

66640537 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90720, while the sum is 37.

The square root of 66640537 is about 8163.3655436958. The cubic root of 66640537 is about 405.4271508120.

The spelling of 66640537 in words is "sixty-six million, six hundred forty thousand, five hundred thirty-seven".