1721625 has 16 divisors (see below), whose sum is σ = 2865408. Its totient is φ = 918000.

The previous prime is 1721593. The next prime is 1721633. The reversal of 1721625 is 5261271.

It is not a de Polignac number, because 1721625 - 2⁵ = 1721593 is a prime.

1721625 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1721595 and 1721604.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1921 + ... + 2670.

It is an arithmetic number, because the mean of its divisors is an integer number (179088).

2^1721625 is an apocalyptic number.

1721625 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1721625 is a deficient number, since it is larger than the sum of its proper divisors (1143783).

1721625 is an equidigital number, since it uses as much as digits as its factorization.

1721625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4609 (or 4599 counting only the distinct ones).

The product of its digits is 840, while the sum is 24.

The square root of 1721625 is about 1312.1070840446. The cubic root of 1721625 is about 119.8522487099.

Adding to 1721625 its reverse (5261271), we get a palindrome (6982896).

It can be divided in two parts, 1721 and 625, that added together give a triangular number (2346 = T₆₈).

The spelling of 1721625 in words is "one million, seven hundred twenty-one thousand, six hundred twenty-five".