21484237 has 2 divisors, whose sum is σ = 21484238. Its totient is φ = 21484236.

The previous prime is 21484213. The next prime is 21484241. The reversal of 21484237 is 73248412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15848361 + 5635876 = 3981^2 + 2374^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21484237 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21484199 and 21484208.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21484537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10742118 + 10742119.

It is an arithmetic number, because the mean of its divisors is an integer number (10742119).

Almost surely, 2^21484237 is an apocalyptic number.

It is an amenable number.

21484237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21484237 is an equidigital number, since it uses as much as digits as its factorization.

21484237 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 31.

The square root of 21484237 is about 4635.1091680779. The cubic root of 21484237 is about 277.9969161019.

The spelling of 21484237 in words is "twenty-one million, four hundred eighty-four thousand, two hundred thirty-seven".