1621619 has 2 divisors, whose sum is σ = 1621620. Its totient is φ = 1621618.

The previous prime is 1621597. The next prime is 1621621. The reversal of 1621619 is 9161261.

It is a strong prime.

It is an emirp because it is prime and its reverse (9161261) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1621619 - 2⁸ = 1621363 is a prime.

It is a super-2 number, since 2×1621619² = 5259296362322, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 1621621, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1621639) 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, 810809 + 810810.

It is an arithmetic number, because the mean of its divisors is an integer number (810810).

2^1621619 is an apocalyptic number.

1621619 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621619 is an equidigital number, since it uses as much as digits as its factorization.

1621619 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 26.

The square root of 1621619 is about 1273.4280505784. The cubic root of 1621619 is about 117.4851407194.

The spelling of 1621619 in words is "one million, six hundred twenty-one thousand, six hundred nineteen".