691371449 has 4 divisors (see below), whose sum is σ = 727759440. Its totient is φ = 654983460.

The previous prime is 691371433. The next prime is 691371451. The reversal of 691371449 is 944173196.

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 691371449 - 2⁴ = 691371433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691371409) 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, 18193967 + ... + 18194004.

It is an arithmetic number, because the mean of its divisors is an integer number (181939860).

Almost surely, 2^691371449 is an apocalyptic number.

It is an amenable number.

691371449 is a deficient number, since it is larger than the sum of its proper divisors (36387991).

691371449 is a wasteful number, since it uses less digits than its factorization.

691371449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36387990.

The product of its digits is 163296, while the sum is 44.

The square root of 691371449 is about 26293.9431999082. The cubic root of 691371449 is about 884.2406582038.

The spelling of 691371449 in words is "six hundred ninety-one million, three hundred seventy-one thousand, four hundred forty-nine".