21010232421 has 12 divisors (see below), whose sum is σ = 30352034700. Its totient is φ = 14005011840.

The previous prime is 21010232401. The next prime is 21010232437. The reversal of 21010232421 is 12423201012.

It is a happy number.

21010232421 is a `hidden beast` number, since 2 + 1 + 0 + 10 + 232 + 421 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 10212113025 + 10798119396 = 101055^2 + 103914^2 .

It is not a de Polignac number, because 21010232421 - 2¹⁸ = 21009970277 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21010232394 and 21010232403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010232401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 75300 + ... + 218381.

It is an arithmetic number, because the mean of its divisors is an integer number (2529336225).

Almost surely, 2^21010232421 is an apocalyptic number.

It is an amenable number.

21010232421 is a deficient number, since it is larger than the sum of its proper divisors (9341802279).

21010232421 is a wasteful number, since it uses less digits than its factorization.

21010232421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 301636 (or 301633 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21010232421 its reverse (12423201012), we get a palindrome (33433433433).

The spelling of 21010232421 in words is "twenty-one billion, ten million, two hundred thirty-two thousand, four hundred twenty-one".