66131501 has 2 divisors, whose sum is σ = 66131502. Its totient is φ = 66131500.

The previous prime is 66131477. The next prime is 66131531. The reversal of 66131501 is 10513166.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40386025 + 25745476 = 6355^2 + 5074^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66131501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66131531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33065750 + 33065751.

It is an arithmetic number, because the mean of its divisors is an integer number (33065751).

Almost surely, 2^66131501 is an apocalyptic number.

It is an amenable number.

66131501 is a deficient number, since it is larger than the sum of its proper divisors (1).

66131501 is an equidigital number, since it uses as much as digits as its factorization.

66131501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 66131501 is about 8132.1277043588. The cubic root of 66131501 is about 404.3922215312.

Adding to 66131501 its reverse (10513166), we get a palindrome (76644667).

The spelling of 66131501 in words is "sixty-six million, one hundred thirty-one thousand, five hundred one".