1621725 has 24 divisors (see below), whose sum is σ = 3065280. Its totient is φ = 741120.

The previous prime is 1621723. The next prime is 1621727. The reversal of 1621725 is 5271261.

It is an interprime number because it is at equal distance from previous prime (1621723) and next prime (1621727).

It is not a de Polignac number, because 1621725 - 2¹ = 1621723 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1621695 and 1621704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621721) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1020 + ... + 2069.

It is an arithmetic number, because the mean of its divisors is an integer number (127720).

2^1621725 is an apocalyptic number.

1621725 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1621725 is a deficient number, since it is larger than the sum of its proper divisors (1443555).

1621725 is a wasteful number, since it uses less digits than its factorization.

1621725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3109 (or 3104 counting only the distinct ones).

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

The square root of 1621725 is about 1273.4696698391. The cubic root of 1621725 is about 117.4877005384.

Adding to 1621725 its reverse (5271261), we get a palindrome (6892986).

It can be divided in two parts, 1621 and 725, that added together give a triangular number (2346 = T₆₈).

The spelling of 1621725 in words is "one million, six hundred twenty-one thousand, seven hundred twenty-five".