65109156721 has 4 divisors (see below), whose sum is σ = 74410464832. Its totient is φ = 55807848612.

The previous prime is 65109156713. The next prime is 65109156757. The reversal of 65109156721 is 12765190156.

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 not a de Polignac number, because 65109156721 - 2³ = 65109156713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65109156221) 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, 4650654045 + ... + 4650654058.

It is an arithmetic number, because the mean of its divisors is an integer number (18602616208).

Almost surely, 2^65109156721 is an apocalyptic number.

It is an amenable number.

65109156721 is a deficient number, since it is larger than the sum of its proper divisors (9301308111).

65109156721 is an equidigital number, since it uses as much as digits as its factorization.

65109156721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9301308110.

The product of its (nonzero) digits is 113400, while the sum is 43.

The spelling of 65109156721 in words is "sixty-five billion, one hundred nine million, one hundred fifty-six thousand, seven hundred twenty-one".