1620920 has 48 divisors (see below), whose sum is σ = 4247640. Its totient is φ = 555072.

The previous prime is 1620917. The next prime is 1620923. The reversal of 1620920 is 290261.

It is an interprime number because it is at equal distance from previous prime (1620917) and next prime (1620923).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 1620892 and 1620901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1620923) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1547 + ... + 2373.

2^1620920 is an apocalyptic number.

1620920 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 1620920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2123820).

1620920 is an abundant number, since it is smaller than the sum of its proper divisors (2626720).

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

1620920 is a wasteful number, since it uses less digits than its factorization.

1620920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 852 (or 841 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 1620920 is about 1273.1535649716. The cubic root of 1620920 is about 117.4682576094.

Subtracting from 1620920 its sum of digits (20), we obtain a triangular number (1620900 = T₁₈₀₀).

The spelling of 1620920 in words is "one million, six hundred twenty thousand, nine hundred twenty".