1621404 has 24 divisors (see below), whose sum is σ = 4203920. Its totient is φ = 540432.

The previous prime is 1621397. The next prime is 1621421. The reversal of 1621404 is 4041261.

1621404 is a `hidden beast` number, since 1 + 621 + 40 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7399 + ... + 7614.

2^1621404 is an apocalyptic number.

It is an amenable number.

1621404 is an abundant number, since it is smaller than the sum of its proper divisors (2582516).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1621404 is a wasteful number, since it uses less digits than its factorization.

1621404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15026 (or 15018 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 1621404 is about 1273.3436299758. The cubic root of 1621404 is about 117.4799482910.

Adding to 1621404 its reverse (4041261), we get a palindrome (5662665).

It can be divided in two parts, 1621 and 404, that added together give a square (2025 = 45²).

The spelling of 1621404 in words is "one million, six hundred twenty-one thousand, four hundred four".