1621723 has 2 divisors, whose sum is σ = 1621724. Its totient is φ = 1621722.

The previous prime is 1621721. The next prime is 1621727. The reversal of 1621723 is 3271261.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1621723 - 2¹ = 1621721 is a prime.

Together with 1621721, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 1621694 and 1621703.

It is not a weakly prime, because it can be changed into another prime (1621721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810861 + 810862.

It is an arithmetic number, because the mean of its divisors is an integer number (810862).

2^1621723 is an apocalyptic number.

1621723 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621723 is an equidigital number, since it uses as much as digits as its factorization.

1621723 is an evil number, because the sum of its binary digits is even.

The product of its digits is 504, while the sum is 22.

The square root of 1621723 is about 1273.4688845826. The cubic root of 1621723 is about 117.4876522410.

Adding to 1621723 its reverse (3271261), we get a palindrome (4892984).

The spelling of 1621723 in words is "one million, six hundred twenty-one thousand, seven hundred twenty-three".