21301947 has 20 divisors (see below), whose sum is σ = 31948840. Its totient is φ = 14144544.

The previous prime is 21301937. The next prime is 21301949. The reversal of 21301947 is 74910312.

It is not a de Polignac number, because 21301947 - 2⁸ = 21301691 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21301947.

It is not an unprimeable number, because it can be changed into a prime (21301949) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 32808 + ... + 33450.

It is an arithmetic number, because the mean of its divisors is an integer number (1597442).

Almost surely, 2^21301947 is an apocalyptic number.

21301947 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21301947 is a deficient number, since it is larger than the sum of its proper divisors (10646893).

21301947 is an equidigital number, since it uses as much as digits as its factorization.

21301947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1064 (or 1055 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21301947 is about 4615.4032326548. The cubic root of 21301947 is about 277.2084300579.

The spelling of 21301947 in words is "twenty-one million, three hundred one thousand, nine hundred forty-seven".