21421430401 has 6 divisors (see below), whose sum is σ = 24918806850. Its totient is φ = 18361226016.

The previous prime is 21421430383. The next prime is 21421430417. The reversal of 21421430401 is 10403412412.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 13895694400 + 7525736001 = 117880^2 + 86751^2 .

It is not a de Polignac number, because 21421430401 - 2²¹ = 21419333249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21421430441) 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, 218585976 + ... + 218586073.

It is an arithmetic number, because the mean of its divisors is an integer number (4153134475).

Almost surely, 2^21421430401 is an apocalyptic number.

It is an amenable number.

21421430401 is a deficient number, since it is larger than the sum of its proper divisors (3497376449).

21421430401 is an equidigital number, since it uses as much as digits as its factorization.

21421430401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437172063 (or 437172056 counting only the distinct ones).

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

Adding to 21421430401 its reverse (10403412412), we get a palindrome (31824842813).

The spelling of 21421430401 in words is "twenty-one billion, four hundred twenty-one million, four hundred thirty thousand, four hundred one".