21010234421 has 6 divisors (see below), whose sum is σ = 23093894166. Its totient is φ = 19100213000.

The previous prime is 21010234411. The next prime is 21010234433. The reversal of 21010234421 is 12443201012.

It can be written as a sum of positive squares in only one way, i.e., 18303113521 + 2707120900 = 135289^2 + 52030^2 .

It is not a de Polignac number, because 21010234421 - 2²⁶ = 20943125557 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21010234393 and 21010234402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010234411) 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, 86819030 + ... + 86819271.

It is an arithmetic number, because the mean of its divisors is an integer number (3848982361).

Almost surely, 2^21010234421 is an apocalyptic number.

It is an amenable number.

21010234421 is a deficient number, since it is larger than the sum of its proper divisors (2083659745).

21010234421 is a wasteful number, since it uses less digits than its factorization.

21010234421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173638323 (or 173638312 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 21010234421 its reverse (12443201012), we get a palindrome (33453435433).

The spelling of 21010234421 in words is "twenty-one billion, ten million, two hundred thirty-four thousand, four hundred twenty-one".