21447801 has 8 divisors (see below), whose sum is σ = 31774560. Its totient is φ = 14298516.

The previous prime is 21447787. The next prime is 21447851. The reversal of 21447801 is 10874412.

It is not a de Polignac number, because 21447801 - 2⁹ = 21447289 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 794363 = 21447801 / (2 + 1 + 4 + 4 + 7 + 8 + 0 + 1).

It is not an unprimeable number, because it can be changed into a prime (21447851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 397155 + ... + 397208.

It is an arithmetic number, because the mean of its divisors is an integer number (3971820).

Almost surely, 2^21447801 is an apocalyptic number.

It is an amenable number.

21447801 is a deficient number, since it is larger than the sum of its proper divisors (10326759).

21447801 is an equidigital number, since it uses as much as digits as its factorization.

21447801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 794372 (or 794366 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 21447801 is about 4631.1770642030. The cubic root of 21447801 is about 277.8396717131.

The spelling of 21447801 in words is "twenty-one million, four hundred forty-seven thousand, eight hundred one".