1021009920 has 224 divisors, whose sum is σ = 3736896768. Its totient is φ = 233177088.

The previous prime is 1021009903. The next prime is 1021009933. The reversal of 1021009920 is 299001201.

It is a tau number, because it is divible by the number of its divisors (224).

It is a super-2 number, since 2×1021009920² = 2084922513476812800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 859567 + ... + 860753.

Almost surely, 2^1021009920 is an apocalyptic number.

1021009920 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 1021009920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1868448384).

1021009920 is an abundant number, since it is smaller than the sum of its proper divisors (2715886848).

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

1021009920 is an equidigital number, since it uses as much as digits as its factorization.

1021009920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1228 (or 1204 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 1021009920 is about 31953.2458445148. The cubic root of 1021009920 is about 1006.9548249427.

The spelling of 1021009920 in words is "one billion, twenty-one million, nine thousand, nine hundred twenty".