20802487 has 4 divisors (see below), whose sum is σ = 20823696. Its totient is φ = 20781280.

The previous prime is 20802469. The next prime is 20802499. The reversal of 20802487 is 78420802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78420802 = 2 ⋅39210401.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20802487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20802427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9058 + ... + 11119.

It is an arithmetic number, because the mean of its divisors is an integer number (5205924).

Almost surely, 2^20802487 is an apocalyptic number.

20802487 is a deficient number, since it is larger than the sum of its proper divisors (21209).

20802487 is a wasteful number, since it uses less digits than its factorization.

20802487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21208.

The product of its (nonzero) digits is 7168, while the sum is 31.

The square root of 20802487 is about 4560.9743476586. The cubic root of 20802487 is about 275.0247338635.

The spelling of 20802487 in words is "twenty million, eight hundred two thousand, four hundred eighty-seven".