6899721 has 4 divisors (see below), whose sum is σ = 9199632. Its totient is φ = 4599812.

The previous prime is 6899719. The next prime is 6899749. The reversal of 6899721 is 1279986.

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 6899721 - 2¹ = 6899719 is a prime.

It is a super-2 number, since 2×6899721² = 95212299755682, which contains 22 as substring.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (6899791) 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, 1149951 + ... + 1149956.

It is an arithmetic number, because the mean of its divisors is an integer number (2299908).

Almost surely, 2^6899721 is an apocalyptic number.

It is an amenable number.

6899721 is a deficient number, since it is larger than the sum of its proper divisors (2299911).

6899721 is a wasteful number, since it uses less digits than its factorization.

6899721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2299910.

The product of its digits is 54432, while the sum is 42.

The square root of 6899721 is about 2626.7320000335. The cubic root of 6899721 is about 190.3752601997.

The spelling of 6899721 in words is "six million, eight hundred ninety-nine thousand, seven hundred twenty-one".