21002012010 has 72 divisors (see below), whose sum is σ = 63520384356. Its totient is φ = 4800458880.

The previous prime is 21002011999. The next prime is 21002012021. The reversal of 21002012010 is 1021020012.

It is an interprime number because it is at equal distance from previous prime (21002011999) and next prime (21002012021).

It can be written as a sum of positive squares in 2 ways, for example, as 20445854121 + 556157889 = 142989^2 + 23583^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21002011983 and 21002012001.

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 35 ways as a sum of consecutive naturals, for example, 2376771 + ... + 2385590.

Almost surely, 2^21002012010 is an apocalyptic number.

21002012010 is an abundant number, since it is smaller than the sum of its proper divisors (42518372346).

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

21002012010 is a wasteful number, since it uses less digits than its factorization.

21002012010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4762388 (or 4762378 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21002012010 its reverse (1021020012), we get a palindrome (22023032022).

The spelling of 21002012010 in words is "twenty-one billion, two million, twelve thousand, ten".