549531691 has 4 divisors (see below), whose sum is σ = 551088792. Its totient is φ = 547974592.

The previous prime is 549531649. The next prime is 549531707. The reversal of 549531691 is 196135945.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 549531691 - 2²⁷ = 415313963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (549531641) 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, 778021 + ... + 778726.

It is an arithmetic number, because the mean of its divisors is an integer number (137772198).

Almost surely, 2^549531691 is an apocalyptic number.

549531691 is a deficient number, since it is larger than the sum of its proper divisors (1557101).

549531691 is a wasteful number, since it uses less digits than its factorization.

549531691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1557100.

The product of its digits is 145800, while the sum is 43.

The square root of 549531691 is about 23442.0922914317. The cubic root of 549531691 is about 819.0886618259.

It can be divided in two parts, 54953 and 1691, that added together give a square (56644 = 238²).

The spelling of 549531691 in words is "five hundred forty-nine million, five hundred thirty-one thousand, six hundred ninety-one".