20782571 has 2 divisors, whose sum is σ = 20782572. Its totient is φ = 20782570.

The previous prime is 20782543. The next prime is 20782579. The reversal of 20782571 is 17528702.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20782571 is a prime.

It is not a weakly prime, because it can be changed into another prime (20782579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10391285 + 10391286.

It is an arithmetic number, because the mean of its divisors is an integer number (10391286).

Almost surely, 2^20782571 is an apocalyptic number.

20782571 is a deficient number, since it is larger than the sum of its proper divisors (1).

20782571 is an equidigital number, since it uses as much as digits as its factorization.

20782571 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7840, while the sum is 32.

The square root of 20782571 is about 4558.7905194251. The cubic root of 20782571 is about 274.9369376059.

The spelling of 20782571 in words is "twenty million, seven hundred eighty-two thousand, five hundred seventy-one".