66961013 has 4 divisors (see below), whose sum is σ = 76526880. Its totient is φ = 57395148.

The previous prime is 66961007. The next prime is 66961031. The reversal of 66961013 is 31016966.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31016966 = 2 ⋅15508483.

It is a cyclic number.

It is not a de Polignac number, because 66961013 - 2⁸ = 66960757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66961003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4782923 + ... + 4782936.

It is an arithmetic number, because the mean of its divisors is an integer number (19131720).

Almost surely, 2^66961013 is an apocalyptic number.

It is an amenable number.

66961013 is a deficient number, since it is larger than the sum of its proper divisors (9565867).

66961013 is an equidigital number, since it uses as much as digits as its factorization.

66961013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9565866.

The product of its (nonzero) digits is 5832, while the sum is 32.

The square root of 66961013 is about 8182.9709152605. The cubic root of 66961013 is about 406.0760148706.

Adding to 66961013 its reverse (31016966), we get a palindrome (97977979).

The spelling of 66961013 in words is "sixty-six million, nine hundred sixty-one thousand, thirteen".