693721381 has 2 divisors, whose sum is σ = 693721382. Its totient is φ = 693721380.

The previous prime is 693721367. The next prime is 693721421. The reversal of 693721381 is 183127396.

It is an a-pointer prime, because the next prime (693721421) can be obtained adding 693721381 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 513249025 + 180472356 = 22655^2 + 13434^2 .

It is a cyclic number.

It is not a de Polignac number, because 693721381 - 2⁵ = 693721349 is a prime.

It is a super-2 number, since 2×693721381² = 962498708913094322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (693721361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 346860690 + 346860691.

It is an arithmetic number, because the mean of its divisors is an integer number (346860691).

Almost surely, 2^693721381 is an apocalyptic number.

It is an amenable number.

693721381 is a deficient number, since it is larger than the sum of its proper divisors (1).

693721381 is an equidigital number, since it uses as much as digits as its factorization.

693721381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432, while the sum is 40.

The square root of 693721381 is about 26338.5910974752. The cubic root of 693721381 is about 885.2413530930.

The spelling of 693721381 in words is "six hundred ninety-three million, seven hundred twenty-one thousand, three hundred eighty-one".