1620403 has 2 divisors, whose sum is σ = 1620404. Its totient is φ = 1620402.

The previous prime is 1620391. The next prime is 1620413. The reversal of 1620403 is 3040261.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1620403 - 2⁵ = 1620371 is a prime.

It is not a weakly prime, because it can be changed into another prime (1620413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810201 + 810202.

It is an arithmetic number, because the mean of its divisors is an integer number (810202).

2^1620403 is an apocalyptic number.

1620403 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620403 is an equidigital number, since it uses as much as digits as its factorization.

1620403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 1620403 is about 1272.9505096429. The cubic root of 1620403 is about 117.4557672650.

Adding to 1620403 its reverse (3040261), we get a palindrome (4660664).

The spelling of 1620403 in words is "one million, six hundred twenty thousand, four hundred three".