21485547 has 8 divisors (see below), whose sum is σ = 31830480. Its totient is φ = 14323680.

The previous prime is 21485543. The next prime is 21485557. The reversal of 21485547 is 74558412.

It is not a de Polignac number, because 21485547 - 2² = 21485543 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21485543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 397854 + ... + 397907.

It is an arithmetic number, because the mean of its divisors is an integer number (3978810).

Almost surely, 2^21485547 is an apocalyptic number.

21485547 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21485547 is a deficient number, since it is larger than the sum of its proper divisors (10344933).

21485547 is an equidigital number, since it uses as much as digits as its factorization.

21485547 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 795770 (or 795764 counting only the distinct ones).

The product of its digits is 44800, while the sum is 36.

The square root of 21485547 is about 4635.2504786689. The cubic root of 21485547 is about 278.0025662686.

The spelling of 21485547 in words is "twenty-one million, four hundred eighty-five thousand, five hundred forty-seven".