21231021512 has 32 divisors (see below), whose sum is σ = 40542353280. Its totient is φ = 10421013120.

The previous prime is 21231021509. The next prime is 21231021517. The reversal of 21231021512 is 21512013212.

It is a super-2 number, since 2×21231021512² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21231021517) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52133 + ... + 212555.

It is an arithmetic number, because the mean of its divisors is an integer number (1266948540).

Almost surely, 2^21231021512 is an apocalyptic number.

It is an amenable number.

21231021512 is a deficient number, since it is larger than the sum of its proper divisors (19311331768).

21231021512 is a wasteful number, since it uses less digits than its factorization.

21231021512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160733 (or 160729 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 21231021512 its reverse (21512013212), we get a palindrome (42743034724).

The spelling of 21231021512 in words is "twenty-one billion, two hundred thirty-one million, twenty-one thousand, five hundred twelve".