21478453 has 2 divisors, whose sum is σ = 21478454. Its totient is φ = 21478452.

The previous prime is 21478447. The next prime is 21478489. The reversal of 21478453 is 35487412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12096484 + 9381969 = 3478^2 + 3063^2 .

It is a cyclic number.

It is not a de Polignac number, because 21478453 - 2¹³ = 21470261 is a prime.

It is a super-2 number, since 2×21478453² = 922647886546418, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21478433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10739226 + 10739227.

It is an arithmetic number, because the mean of its divisors is an integer number (10739227).

Almost surely, 2^21478453 is an apocalyptic number.

It is an amenable number.

21478453 is a deficient number, since it is larger than the sum of its proper divisors (1).

21478453 is an equidigital number, since it uses as much as digits as its factorization.

21478453 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26880, while the sum is 34.

The square root of 21478453 is about 4634.4851925538. The cubic root of 21478453 is about 277.9719663604.

The spelling of 21478453 in words is "twenty-one million, four hundred seventy-eight thousand, four hundred fifty-three".