691620539 has 8 divisors (see below), whose sum is σ = 747698640. Its totient is φ = 637510176.

The previous prime is 691620499. The next prime is 691620541. The reversal of 691620539 is 935026196.

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 691620539 - 2¹⁶ = 691555003 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 691620496 and 691620505.

It is not an unprimeable number, because it can be changed into a prime (691620599) 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, 491204 + ... + 492609.

It is an arithmetic number, because the mean of its divisors is an integer number (93462330).

Almost surely, 2^691620539 is an apocalyptic number.

691620539 is a deficient number, since it is larger than the sum of its proper divisors (56078101).

691620539 is a wasteful number, since it uses less digits than its factorization.

691620539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 983869.

The product of its (nonzero) digits is 87480, while the sum is 41.

The square root of 691620539 is about 26298.6794155144. The cubic root of 691620539 is about 884.3468380099.

The spelling of 691620539 in words is "six hundred ninety-one million, six hundred twenty thousand, five hundred thirty-nine".