66137557 has 2 divisors, whose sum is σ = 66137558. Its totient is φ = 66137556.

The previous prime is 66137543. The next prime is 66137567. The reversal of 66137557 is 75573166.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52403121 + 13734436 = 7239^2 + 3706^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66137557 is a prime.

It is a Chen prime.

It is the 8133-rd Hogben number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66137567) by changing a digit.

It is a nontrivial repunit in base 8132.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33068778 + 33068779.

It is an arithmetic number, because the mean of its divisors is an integer number (33068779).

Almost surely, 2^66137557 is an apocalyptic number.

It is an amenable number.

66137557 is a deficient number, since it is larger than the sum of its proper divisors (1).

66137557 is an equidigital number, since it uses as much as digits as its factorization.

66137557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 132300, while the sum is 40.

The square root of 66137557 is about 8132.5000461113. The cubic root of 66137557 is about 404.4045652429.

The spelling of 66137557 in words is "sixty-six million, one hundred thirty-seven thousand, five hundred fifty-seven".