1620900 has 54 divisors (see below), whose sum is σ = 5083442. Its totient is φ = 432000.

The previous prime is 1620893. The next prime is 1620917. The reversal of 1620900 is 90261.

1620900 is a nontrivial binomial coefficient, being equal to C(1801, 2).

It can be written as a sum of positive squares in 3 ways, for example, as 2916 + 1617984 = 54^2 + 1272^2 .

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

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 17 ways as a sum of consecutive naturals, for example, 1 + ... + 1800.

2^1620900 is an apocalyptic number.

1620900 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1620900 is the 1800-th triangular number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1620900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2541721).

1620900 is an abundant number, since it is smaller than the sum of its proper divisors (3462542).

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

1620900 is a wasteful number, since it uses less digits than its factorization.

1620900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1821 (or 1811 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 1620900 is about 1273.1457104354. The cubic root of 1620900 is about 117.4677744733.

The spelling of 1620900 in words is "one million, six hundred twenty thousand, nine hundred".