691890143 has 24 divisors (see below), whose sum is σ = 823968288. Its totient is φ = 579074496.

The previous prime is 691890127. The next prime is 691890169. The reversal of 691890143 is 341098196.

It is not a de Polignac number, because 691890143 - 2⁴ = 691890127 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 691890143.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691890103) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 682505 + ... + 683517.

It is an arithmetic number, because the mean of its divisors is an integer number (34332012).

Almost surely, 2^691890143 is an apocalyptic number.

691890143 is a deficient number, since it is larger than the sum of its proper divisors (132078145).

691890143 is a wasteful number, since it uses less digits than its factorization.

691890143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1343 (or 1336 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 691890143 is about 26303.8047247922. The cubic root of 691890143 is about 884.4617336104.

The spelling of 691890143 in words is "six hundred ninety-one million, eight hundred ninety thousand, one hundred forty-three".