1621920 has 96 divisors (see below), whose sum is σ = 5322240. Its totient is φ = 414720.

The previous prime is 1621909. The next prime is 1621931. The reversal of 1621920 is 291261.

It is an interprime number because it is at equal distance from previous prime (1621909) and next prime (1621931).

It is a tau number, because it is divible by the number of its divisors (96).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14826 + ... + 14934.

It is an arithmetic number, because the mean of its divisors is an integer number (55440).

2^1621920 is an apocalyptic number.

1621920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1621920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2661120).

1621920 is an abundant number, since it is smaller than the sum of its proper divisors (3700320).

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

1621920 is a wasteful number, since it uses less digits than its factorization.

1621920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 1621920 is about 1273.5462300207. The cubic root of 1621920 is about 117.4924093482.

The spelling of 1621920 in words is "one million, six hundred twenty-one thousand, nine hundred twenty".