66156634663501 has 2 divisors, whose sum is σ = 66156634663502. Its totient is φ = 66156634663500.

The previous prime is 66156634663429. The next prime is 66156634663529. The reversal of 66156634663501 is 10536643665166.

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., 65673616613476 + 483018050025 = 8103926^2 + 694995^2 .

It is a cyclic number.

It is not a de Polignac number, because 66156634663501 - 2¹⁵ = 66156634630733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66156634663571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33078317331750 + 33078317331751.

It is an arithmetic number, because the mean of its divisors is an integer number (33078317331751).

Almost surely, 2^{66156634663501} is an apocalyptic number.

It is an amenable number.

66156634663501 is a deficient number, since it is larger than the sum of its proper divisors (1).

66156634663501 is an equidigital number, since it uses as much as digits as its factorization.

66156634663501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41990400, while the sum is 58.

The spelling of 66156634663501 in words is "sixty-six trillion, one hundred fifty-six billion, six hundred thirty-four million, six hundred sixty-three thousand, five hundred one".