1638431 has 2 divisors, whose sum is σ = 1638432. Its totient is φ = 1638430.

The previous prime is 1638353. The next prime is 1638463. The reversal of 1638431 is 1348361.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1638431 - 2¹⁰ = 1637407 is a prime.

It is a super-2 number, since 2×1638431² = 5368912283522, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1638431.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1638031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819215 + 819216.

It is an arithmetic number, because the mean of its divisors is an integer number (819216).

2^1638431 is an apocalyptic number.

1638431 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638431 is an equidigital number, since it uses as much as digits as its factorization.

1638431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 26.

The square root of 1638431 is about 1280.0121093177. The cubic root of 1638431 is about 117.8897514738.

The spelling of 1638431 in words is "one million, six hundred thirty-eight thousand, four hundred thirty-one".