21682145 has 8 divisors (see below), whose sum is σ = 26445480. Its totient is φ = 17061120.

The previous prime is 21682139. The next prime is 21682151. The reversal of 21682145 is 54128612.

It is an interprime number because it is at equal distance from previous prime (21682139) and next prime (21682151).

It can be written as a sum of positive squares in 4 ways, for example, as 2611456 + 19070689 = 1616^2 + 4367^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21682145 - 2¹² = 21678049 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35240 + ... + 35849.

It is an arithmetic number, because the mean of its divisors is an integer number (3305685).

Almost surely, 2^21682145 is an apocalyptic number.

It is an amenable number.

21682145 is a deficient number, since it is larger than the sum of its proper divisors (4763335).

21682145 is an equidigital number, since it uses as much as digits as its factorization.

21682145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71155.

The product of its digits is 3840, while the sum is 29.

The square root of 21682145 is about 4656.4090241301. The cubic root of 21682145 is about 278.8479235279.

The spelling of 21682145 in words is "twenty-one million, six hundred eighty-two thousand, one hundred forty-five".