21337047 has 8 divisors (see below), whose sum is σ = 31610480. Its totient is φ = 14224680.

The previous prime is 21337037. The next prime is 21337061. The reversal of 21337047 is 74073312.

It is not a de Polignac number, because 21337047 - 2¹⁸ = 21074903 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: 790261 = 21337047 / (2 + 1 + 3 + 3 + 7 + 0 + 4 + 7).

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 21337047.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21337037) 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, 395104 + ... + 395157.

It is an arithmetic number, because the mean of its divisors is an integer number (3951310).

Almost surely, 2^21337047 is an apocalyptic number.

21337047 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21337047 is a deficient number, since it is larger than the sum of its proper divisors (10273433).

21337047 is an equidigital number, since it uses as much as digits as its factorization.

21337047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 790270 (or 790264 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 27.

The square root of 21337047 is about 4619.2041522323. The cubic root of 21337047 is about 277.3606020106.

It can be divided in two parts, 2133 and 7047, that added together give a triangular number (9180 = T₁₃₅).

The spelling of 21337047 in words is "twenty-one million, three hundred thirty-seven thousand, forty-seven".