691742389 has 8 divisors (see below), whose sum is σ = 745276952. Its totient is φ = 638254080.

The previous prime is 691742357. The next prime is 691742453. The reversal of 691742389 is 983247196.

It can be written as a sum of positive squares in 4 ways, for example, as 69639025 + 622103364 = 8345^2 + 24942^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 691742389 - 2⁵ = 691742357 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691742309) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23449 + ... + 43969.

It is an arithmetic number, because the mean of its divisors is an integer number (93159619).

Almost surely, 2^691742389 is an apocalyptic number.

It is an amenable number.

691742389 is a deficient number, since it is larger than the sum of its proper divisors (53534563).

691742389 is a wasteful number, since it uses less digits than its factorization.

691742389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23127.

The product of its digits is 653184, while the sum is 49.

The square root of 691742389 is about 26300.9959697347. The cubic root of 691742389 is about 884.3987698273.

The spelling of 691742389 in words is "six hundred ninety-one million, seven hundred forty-two thousand, three hundred eighty-nine".