21010183720 has 64 divisors (see below), whose sum is σ = 50616219600. Its totient is φ = 7820820480.

The previous prime is 21010183651. The next prime is 21010183741. The reversal of 21010183720 is 2738101012.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 9796644484 + 11213539236 = 98978^2 + 105894^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 113061 + ... + 234100.

Almost surely, 2^21010183720 is an apocalyptic number.

21010183720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21010183720 is an abundant number, since it is smaller than the sum of its proper divisors (29606035880).

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

21010183720 is a wasteful number, since it uses less digits than its factorization.

21010183720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347278 (or 347274 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 25.

Adding to 21010183720 its reverse (2738101012), we get a palindrome (23748284732).

The spelling of 21010183720 in words is "twenty-one billion, ten million, one hundred eighty-three thousand, seven hundred twenty".