1021115540 has 24 divisors (see below), whose sum is σ = 2270481192. Its totient is φ = 384419840.

The previous prime is 1021115533. The next prime is 1021115569. The reversal of 1021115540 is 455111201.

It can be written as a sum of positive squares in 4 ways, for example, as 100721296 + 920394244 = 10036^2 + 30338^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

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, 1501301 + ... + 1501980.

It is an arithmetic number, because the mean of its divisors is an integer number (94603383).

Almost surely, 2^1021115540 is an apocalyptic number.

1021115540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1021115540 is an abundant number, since it is smaller than the sum of its proper divisors (1249365652).

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

1021115540 is a wasteful number, since it uses less digits than its factorization.

1021115540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3003307 (or 3003305 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 20.

The square root of 1021115540 is about 31954.8985290206. The cubic root of 1021115540 is about 1006.9895457615.

Adding to 1021115540 its reverse (455111201), we get a palindrome (1476226741).

The spelling of 1021115540 in words is "one billion, twenty-one million, one hundred fifteen thousand, five hundred forty".