691861439 has 16 divisors (see below), whose sum is σ = 723492000. Its totient is φ = 660799104.

The previous prime is 691861411. The next prime is 691861453. The reversal of 691861439 is 934168196.

It is a de Polignac number, because none of the positive numbers 2^k-691861439 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 691861393 and 691861402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691861139) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1982237 + ... + 1982585.

It is an arithmetic number, because the mean of its divisors is an integer number (45218250).

Almost surely, 2^691861439 is an apocalyptic number.

691861439 is a deficient number, since it is larger than the sum of its proper divisors (31630561).

691861439 is a wasteful number, since it uses less digits than its factorization.

691861439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 922.

The product of its digits is 279936, while the sum is 47.

The square root of 691861439 is about 26303.2590946445. The cubic root of 691861439 is about 884.4495024101.

The spelling of 691861439 in words is "six hundred ninety-one million, eight hundred sixty-one thousand, four hundred thirty-nine".