21400547 has 8 divisors (see below), whose sum is σ = 24768000. Its totient is φ = 18110664.

The previous prime is 21400523. The next prime is 21400583. The reversal of 21400547 is 74500412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21400547 - 2²⁰ = 20351971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21400507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18797 + ... + 19902.

It is an arithmetic number, because the mean of its divisors is an integer number (3096000).

Almost surely, 2^21400547 is an apocalyptic number.

21400547 is a deficient number, since it is larger than the sum of its proper divisors (3367453).

21400547 is an equidigital number, since it uses as much as digits as its factorization.

21400547 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38785.

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 21400547 is about 4626.0725242910. The cubic root of 21400547 is about 277.6354753377.

Adding to 21400547 its reverse (74500412), we get a palindrome (95900959).

The spelling of 21400547 in words is "twenty-one million, four hundred thousand, five hundred forty-seven".