61666722929 has 4 divisors (see below), whose sum is σ = 70476254784. Its totient is φ = 52857191076.

The previous prime is 61666722911. The next prime is 61666722973. The reversal of 61666722929 is 92922766616.

It is a happy number.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61666722929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61666722979) 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, 4404765917 + ... + 4404765930.

It is an arithmetic number, because the mean of its divisors is an integer number (17619063696).

Almost surely, 2^61666722929 is an apocalyptic number.

It is an amenable number.

61666722929 is a deficient number, since it is larger than the sum of its proper divisors (8809531855).

61666722929 is an equidigital number, since it uses as much as digits as its factorization.

61666722929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8809531854.

The product of its digits is 5878656, while the sum is 56.

The spelling of 61666722929 in words is "sixty-one billion, six hundred sixty-six million, seven hundred twenty-two thousand, nine hundred twenty-nine".