691026402 has 48 divisors (see below), whose sum is σ = 1547864640. Its totient is φ = 205439520.

The previous prime is 691026373. The next prime is 691026419. The reversal of 691026402 is 204620196.

It is a super-2 number, since 2×691026402² = 955034976522131208, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 691026402.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 29499 + ... + 47457.

It is an arithmetic number, because the mean of its divisors is an integer number (32247180).

Almost surely, 2^691026402 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691026402, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (773932320).

691026402 is an abundant number, since it is smaller than the sum of its proper divisors (856838238).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

691026402 is a wasteful number, since it uses less digits than its factorization.

691026402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18039 (or 18028 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 691026402 is about 26287.3810411003. The cubic root of 691026402 is about 884.0935325847.

Adding to 691026402 its reverse (204620196), we get a palindrome (895646598).

The spelling of 691026402 in words is "six hundred ninety-one million, twenty-six thousand, four hundred two".