7639891 has 4 divisors (see below), whose sum is σ = 8731312. Its totient is φ = 6548472.

The previous prime is 7639883. The next prime is 7639913. The reversal of 7639891 is 1989367.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1989367 = 397 ⋅5011.

It is not a de Polignac number, because 7639891 - 2³ = 7639883 is a prime.

It is a super-3 number, since 3×7639891³ (a number of 22 digits) contains 333 as substring.

It is a Duffinian number.

7639891 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (7639831) 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, 545700 + ... + 545713.

It is an arithmetic number, because the mean of its divisors is an integer number (2182828).

Almost surely, 2^7639891 is an apocalyptic number.

7639891 is a deficient number, since it is larger than the sum of its proper divisors (1091421).

7639891 is a wasteful number, since it uses less digits than its factorization.

7639891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1091420.

The product of its digits is 81648, while the sum is 43.

The square root of 7639891 is about 2764.0352747387. The cubic root of 7639891 is about 196.9529034435.

The spelling of 7639891 in words is "seven million, six hundred thirty-nine thousand, eight hundred ninety-one".