691479421 has 8 divisors (see below), whose sum is σ = 710508344. Its totient is φ = 672468480.

The previous prime is 691479419. The next prime is 691479427. The reversal of 691479421 is 124974196.

It can be written as a sum of positive squares in 4 ways, for example, as 606636900 + 84842521 = 24630^2 + 9211^2 .

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 691479421 - 2¹ = 691479419 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 (691479427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 119761 + ... + 125401.

It is an arithmetic number, because the mean of its divisors is an integer number (88813543).

Almost surely, 2^691479421 is an apocalyptic number.

It is an amenable number.

691479421 is a deficient number, since it is larger than the sum of its proper divisors (19028923).

691479421 is a wasteful number, since it uses less digits than its factorization.

691479421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8991.

The product of its digits is 108864, while the sum is 43.

The square root of 691479421 is about 26295.9962922115. The cubic root of 691479421 is about 884.2866866510.

The spelling of 691479421 in words is "six hundred ninety-one million, four hundred seventy-nine thousand, four hundred twenty-one".