690138431 has 4 divisors (see below), whose sum is σ = 690193392. Its totient is φ = 690083472.

The previous prime is 690138377. The next prime is 690138439. The reversal of 690138431 is 134831096.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-690138431 is a prime.

It is a super-2 number, since 2×690138431² = 952582107886283522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 690138391 and 690138400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (690138439) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1646 + ... + 37188.

It is an arithmetic number, because the mean of its divisors is an integer number (172548348).

Almost surely, 2^690138431 is an apocalyptic number.

690138431 is a deficient number, since it is larger than the sum of its proper divisors (54961).

690138431 is a wasteful number, since it uses less digits than its factorization.

690138431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54960.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 690138431 is about 26270.4859300318. The cubic root of 690138431 is about 883.7146826499.

The spelling of 690138431 in words is "six hundred ninety million, one hundred thirty-eight thousand, four hundred thirty-one".