1021697820 has 384 divisors, whose sum is σ = 3800079360. Its totient is φ = 224640000.

The previous prime is 1021697813. The next prime is 1021697821. The reversal of 1021697820 is 287961201.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021697821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 7799155 + ... + 7799285.

It is an arithmetic number, because the mean of its divisors is an integer number (9896040).

Almost surely, 2^1021697820 is an apocalyptic number.

1021697820 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 1021697820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1900039680).

1021697820 is an abundant number, since it is smaller than the sum of its proper divisors (2778381540).

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

1021697820 is a wasteful number, since it uses less digits than its factorization.

1021697820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274 (or 266 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The square root of 1021697820 is about 31964.0081967203. The cubic root of 1021697820 is about 1007.1809176589.

The spelling of 1021697820 in words is "one billion, twenty-one million, six hundred ninety-seven thousand, eight hundred twenty".