21035221440 has 56 divisors (see below), whose sum is σ = 66786831120. Its totient is φ = 5609392128.

The previous prime is 21035221429. The next prime is 21035221469. The reversal of 21035221440 is 4412253012.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21035221440.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10954885 + ... + 10956804.

Almost surely, 2^21035221440 is an apocalyptic number.

21035221440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21035221440 is an abundant number, since it is smaller than the sum of its proper divisors (45751609680).

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

21035221440 is a wasteful number, since it uses less digits than its factorization.

21035221440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21911709 (or 21911699 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

Adding to 21035221440 its reverse (4412253012), we get a palindrome (25447474452).

The spelling of 21035221440 in words is "twenty-one billion, thirty-five million, two hundred twenty-one thousand, four hundred forty".