21010213440 has 84 divisors (see below), whose sum is σ = 72266389884. Its totient is φ = 5602722816.

The previous prime is 21010213423. The next prime is 21010213481. The reversal of 21010213440 is 4431201012.

21010213440 is a `hidden beast` number, since 2 + 1 + 0 + 10 + 213 + 440 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 6151578624 + 14858634816 = 78432^2 + 121896^2 .

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, 3644727 + ... + 3650486.

Almost surely, 2^21010213440 is an apocalyptic number.

21010213440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21010213440 is an abundant number, since it is smaller than the sum of its proper divisors (51256176444).

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

21010213440 is a wasteful number, since it uses less digits than its factorization.

21010213440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7295236 (or 7295223 counting only the distinct ones).

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

Adding to 21010213440 its reverse (4431201012), we get a palindrome (25441414452).

The spelling of 21010213440 in words is "twenty-one billion, ten million, two hundred thirteen thousand, four hundred forty".