21455143 has 2 divisors, whose sum is σ = 21455144. Its totient is φ = 21455142.

The previous prime is 21455117. The next prime is 21455183. The reversal of 21455143 is 34155412.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21455143 - 2⁵ = 21455111 is a prime.

It is a super-2 number, since 2×21455143² = 920646322300898, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21455183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10727571 + 10727572.

It is an arithmetic number, because the mean of its divisors is an integer number (10727572).

Almost surely, 2^21455143 is an apocalyptic number.

21455143 is a deficient number, since it is larger than the sum of its proper divisors (1).

21455143 is an equidigital number, since it uses as much as digits as its factorization.

21455143 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2400, while the sum is 25.

The square root of 21455143 is about 4631.9696674309. The cubic root of 21455143 is about 277.8713714065.

The spelling of 21455143 in words is "twenty-one million, four hundred fifty-five thousand, one hundred forty-three".