21446431 has 2 divisors, whose sum is σ = 21446432. Its totient is φ = 21446430.

The previous prime is 21446417. The next prime is 21446437. The reversal of 21446431 is 13464412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21446431 - 2¹³ = 21438239 is a prime.

It is a super-2 number, since 2×21446431² = 919898805275522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21446396 and 21446405.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21446437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10723215 + 10723216.

It is an arithmetic number, because the mean of its divisors is an integer number (10723216).

Almost surely, 2^21446431 is an apocalyptic number.

21446431 is a deficient number, since it is larger than the sum of its proper divisors (1).

21446431 is an equidigital number, since it uses as much as digits as its factorization.

21446431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 25.

The square root of 21446431 is about 4631.0291512794. The cubic root of 21446431 is about 277.8337558237.

The spelling of 21446431 in words is "twenty-one million, four hundred forty-six thousand, four hundred thirty-one".