7964067721 has 4 divisors (see below), whose sum is σ = 8383229200. Its totient is φ = 7544906244.

The previous prime is 7964067691. The next prime is 7964067751. The reversal of 7964067721 is 1277604697.

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: 1277604697 = 53 ⋅24105749.

It is an interprime number because it is at equal distance from previous prime (7964067691) and next prime (7964067751).

It is a cyclic number.

It is not a de Polignac number, because 7964067721 - 2⁷ = 7964067593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7964067751) 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, 209580711 + ... + 209580748.

It is an arithmetic number, because the mean of its divisors is an integer number (2095807300).

Almost surely, 2^7964067721 is an apocalyptic number.

It is an amenable number.

7964067721 is a deficient number, since it is larger than the sum of its proper divisors (419161479).

7964067721 is a wasteful number, since it uses less digits than its factorization.

7964067721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 419161478.

The product of its (nonzero) digits is 889056, while the sum is 49.

The square root of 7964067721 is about 89241.6254950570. The cubic root of 7964067721 is about 1997.0011491108.

The spelling of 7964067721 in words is "seven billion, nine hundred sixty-four million, sixty-seven thousand, seven hundred twenty-one".