21421023412 has 18 divisors (see below), whose sum is σ = 39187518818. Its totient is φ = 10244836272.

The previous prime is 21421023397. The next prime is 21421023419. The reversal of 21421023412 is 21432012412.

It can be written as a sum of positive squares in only one way, i.e., 20783258896 + 637764516 = 144164^2 + 25254^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421023419) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5059563 + ... + 5063794.

Almost surely, 2^21421023412 is an apocalyptic number.

It is an amenable number.

21421023412 is a deficient number, since it is larger than the sum of its proper divisors (17766495406).

21421023412 is a wasteful number, since it uses less digits than its factorization.

21421023412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10123407 (or 10123382 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

Adding to 21421023412 its reverse (21432012412), we get a palindrome (42853035824).

The spelling of 21421023412 in words is "twenty-one billion, four hundred twenty-one million, twenty-three thousand, four hundred twelve".