2670391721 has 4 divisors (see below), whose sum is σ = 2708002944. Its totient is φ = 2632780500.

The previous prime is 2670391687. The next prime is 2670391723. The reversal of 2670391721 is 1271930762.

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 2670391721 - 2¹⁸ = 2670129577 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2670391723) 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, 18805505 + ... + 18805646.

It is an arithmetic number, because the mean of its divisors is an integer number (677000736).

Almost surely, 2^2670391721 is an apocalyptic number.

It is an amenable number.

2670391721 is a deficient number, since it is larger than the sum of its proper divisors (37611223).

2670391721 is an equidigital number, since it uses as much as digits as its factorization.

2670391721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37611222.

The product of its (nonzero) digits is 31752, while the sum is 38.

The square root of 2670391721 is about 51675.8330460187. The cubic root of 2670391721 is about 1387.3679503798.

The spelling of 2670391721 in words is "two billion, six hundred seventy million, three hundred ninety-one thousand, seven hundred twenty-one".