1620690 has 32 divisors (see below), whose sum is σ = 3939840. Its totient is φ = 426624.

The previous prime is 1620679. The next prime is 1620733. The reversal of 1620690 is 960261.

It is a super-2 number, since 2×1620690² = 5253272152200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1620690.

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, 2367 + ... + 2973.

It is an arithmetic number, because the mean of its divisors is an integer number (123120).

2^1620690 is an apocalyptic number.

1620690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1620690 is an abundant number, since it is smaller than the sum of its proper divisors (2319150).

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

1620690 is a wasteful number, since it uses less digits than its factorization.

1620690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 706.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 1620690 is about 1273.0632348788. The cubic root of 1620690 is about 117.4627013045.

It can be divided in two parts, 16 and 20690, that added together give a triangular number (20706 = T₂₀₃).

The spelling of 1620690 in words is "one million, six hundred twenty thousand, six hundred ninety".