21001220610 has 16 divisors (see below), whose sum is σ = 50402929536. Its totient is φ = 5600325488.

The previous prime is 21001220593. The next prime is 21001220659. The reversal of 21001220610 is 1602210012.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21001220610.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 350020314 + ... + 350020373.

It is an arithmetic number, because the mean of its divisors is an integer number (3150183096).

Almost surely, 2^21001220610 is an apocalyptic number.

21001220610 is an abundant number, since it is smaller than the sum of its proper divisors (29401708926).

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

21001220610 is a wasteful number, since it uses less digits than its factorization.

21001220610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 700040697.

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21001220610 its reverse (1602210012), we get a palindrome (22603430622).

The spelling of 21001220610 in words is "twenty-one billion, one million, two hundred twenty thousand, six hundred ten".