1021212100 has 72 divisors (see below), whose sum is σ = 2352927528. Its totient is φ = 383385600.

The previous prime is 1021212091. The next prime is 1021212107. The reversal of 1021212100 is 12121201.

It can be written as a sum of positive squares in 12 ways, for example, as 114961284 + 906250816 = 10722^2 + 30104^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (1021212107) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 885124 + ... + 886276.

It is an arithmetic number, because the mean of its divisors is an integer number (32679549).

Almost surely, 2^1021212100 is an apocalyptic number.

1021212100 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 1021212100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1176463764).

1021212100 is an abundant number, since it is smaller than the sum of its proper divisors (1331715428).

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

1021212100 is a wasteful number, since it uses less digits than its factorization.

1021212100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1705 (or 1698 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 1021212100 is about 31956.4093727690. The cubic root of 1021212100 is about 1007.0212861611.

Adding to 1021212100 its reverse (12121201), we get a palindrome (1033333301).

The spelling of 1021212100 in words is "one billion, twenty-one million, two hundred twelve thousand, one hundred".