1021820 has 24 divisors (see below), whose sum is σ = 2259600. Its totient is φ = 387072.

The previous prime is 1021807. The next prime is 1021831. The reversal of 1021820 is 281201.

It is a super-2 number, since 2×1021820² = 2088232224800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1021795 and 1021804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 965 + ... + 1724.

It is an arithmetic number, because the mean of its divisors is an integer number (94150).

2^1021820 is an apocalyptic number.

1021820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1021820 is an abundant number, since it is smaller than the sum of its proper divisors (1237780).

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

1021820 is a wasteful number, since it uses less digits than its factorization.

1021820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2717 (or 2715 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 1021820 is about 1010.8511265266. The cubic root of 1021820 is about 100.7221064056.

The spelling of 1021820 in words is "one million, twenty-one thousand, eight hundred twenty".