20776987 has 16 divisors (see below), whose sum is σ = 26035200. Its totient is φ = 16107840.

The previous prime is 20776969. The next prime is 20776991. The reversal of 20776987 is 78967702.

It is not a de Polignac number, because 20776987 - 2¹¹ = 20774939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20776927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17839 + ... + 18967.

It is an arithmetic number, because the mean of its divisors is an integer number (1627200).

Almost surely, 2^20776987 is an apocalyptic number.

20776987 is a deficient number, since it is larger than the sum of its proper divisors (5258213).

20776987 is a wasteful number, since it uses less digits than its factorization.

20776987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1386.

The product of its (nonzero) digits is 296352, while the sum is 46.

The square root of 20776987 is about 4558.1780351364. The cubic root of 20776987 is about 274.9123114359.

The spelling of 20776987 in words is "twenty million, seven hundred seventy-six thousand, nine hundred eighty-seven".