7661391 has 4 divisors (see below), whose sum is σ = 10215192. Its totient is φ = 5107592.

The previous prime is 7661347. The next prime is 7661393. The reversal of 7661391 is 1931667.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1931667 = 3 ⋅643889.

It is a cyclic number.

It is not a de Polignac number, because 7661391 - 2¹⁴ = 7645007 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7661393) 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, 1276896 + ... + 1276901.

It is an arithmetic number, because the mean of its divisors is an integer number (2553798).

Almost surely, 2^7661391 is an apocalyptic number.

7661391 is a deficient number, since it is larger than the sum of its proper divisors (2553801).

7661391 is a wasteful number, since it uses less digits than its factorization.

7661391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2553800.

The product of its digits is 6804, while the sum is 33.

The square root of 7661391 is about 2767.9217835770. The cubic root of 7661391 is about 197.1374838005.

The spelling of 7661391 in words is "seven million, six hundred sixty-one thousand, three hundred ninety-one".