1620431 has 2 divisors, whose sum is σ = 1620432. Its totient is φ = 1620430.

The previous prime is 1620413. The next prime is 1620439. The reversal of 1620431 is 1340261.

Together with previous prime (1620413) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1620431 is a prime.

It is a super-2 number, since 2×1620431² = 5251593251522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1620439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810215 + 810216.

It is an arithmetic number, because the mean of its divisors is an integer number (810216).

2^1620431 is an apocalyptic number.

1620431 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620431 is an equidigital number, since it uses as much as digits as its factorization.

1620431 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 1620431 is about 1272.9615076663. The cubic root of 1620431 is about 117.4564437927.

Adding to 1620431 its reverse (1340261), we get a palindrome (2960692).

The spelling of 1620431 in words is "one million, six hundred twenty thousand, four hundred thirty-one".