21082745 has 16 divisors (see below), whose sum is σ = 25800768. Its totient is φ = 16536000.

The previous prime is 21082729. The next prime is 21082757. The reversal of 21082745 is 54728012.

It is not a de Polignac number, because 21082745 - 2⁴ = 21082729 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 83870 + ... + 84120.

It is an arithmetic number, because the mean of its divisors is an integer number (1612548).

Almost surely, 2^21082745 is an apocalyptic number.

It is an amenable number.

21082745 is a deficient number, since it is larger than the sum of its proper divisors (4718023).

21082745 is a wasteful number, since it uses less digits than its factorization.

21082745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 21082745 is about 4591.5950387638. The cubic root of 21082745 is about 276.2543033529.

The spelling of 21082745 in words is "twenty-one million, eighty-two thousand, seven hundred forty-five".