1021006440 has 48 divisors (see below), whose sum is σ = 3318272100. Its totient is φ = 272268288.

The previous prime is 1021006433. The next prime is 1021006463. The reversal of 1021006440 is 446001201.

1021006440 is a `hidden beast` number, since 1 + 0 + 21 + 0 + 0 + 644 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 978313284 + 42693156 = 31278^2 + 6534^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1417705 + ... + 1418424.

Almost surely, 2^1021006440 is an apocalyptic number.

1021006440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1021006440 is an abundant number, since it is smaller than the sum of its proper divisors (2297265660).

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

1021006440 is a wasteful number, since it uses less digits than its factorization.

1021006440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2836146 (or 2836139 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 1021006440 is about 31953.1913899066. The cubic root of 1021006440 is about 1006.9536809098.

Adding to 1021006440 its reverse (446001201), we get a palindrome (1467007641).

The spelling of 1021006440 in words is "one billion, twenty-one million, six thousand, four hundred forty".