691395021400 has 24 divisors (see below), whose sum is σ = 1607493425220. Its totient is φ = 276558008480.

The previous prime is 691395021397. The next prime is 691395021403. The reversal of 691395021400 is 4120593196.

It is an interprime number because it is at equal distance from previous prime (691395021397) and next prime (691395021403).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691395021403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1728487354 + ... + 1728487753.

Almost surely, 2^691395021400 is an apocalyptic number.

It is an amenable number.

691395021400 is an abundant number, since it is smaller than the sum of its proper divisors (916098403820).

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

691395021400 is a wasteful number, since it uses less digits than its factorization.

691395021400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3456975123 (or 3456975114 counting only the distinct ones).

The product of its (nonzero) digits is 58320, while the sum is 40.

The spelling of 691395021400 in words is "six hundred ninety-one billion, three hundred ninety-five million, twenty-one thousand, four hundred".