21221201502 has 160 divisors (see below), whose sum is σ = 49927705344. Its totient is φ = 6731424000.

The previous prime is 21221201471. The next prime is 21221201503. The reversal of 21221201502 is 20510212212.

21221201502 is a `hidden beast` number, since 21 + 22 + 120 + 1 + 502 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221201503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 52920502 + ... + 52920902.

Almost surely, 2^21221201502 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21221201502, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24963852672).

21221201502 is an abundant number, since it is smaller than the sum of its proper divisors (28706503842).

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

21221201502 is a wasteful number, since it uses less digits than its factorization.

21221201502 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 636 (or 627 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

Adding to 21221201502 its reverse (20510212212), we get a palindrome (41731413714).

The spelling of 21221201502 in words is "twenty-one billion, two hundred twenty-one million, two hundred one thousand, five hundred two".