1620990 has 96 divisors (see below), whose sum is σ = 5031936. Its totient is φ = 354240.

The previous prime is 1620989. The next prime is 1621019. The reversal of 1620990 is 990261.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 19489 + ... + 19571.

It is an arithmetic number, because the mean of its divisors is an integer number (52416).

2^1620990 is an apocalyptic number.

1620990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1620990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2515968).

1620990 is an abundant number, since it is smaller than the sum of its proper divisors (3410946).

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

1620990 is a wasteful number, since it uses less digits than its factorization.

1620990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134 (or 131 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 1620990 is about 1273.1810554670. The cubic root of 1620990 is about 117.4699485544.

The spelling of 1620990 in words is "one million, six hundred twenty thousand, nine hundred ninety".