20513786 has 8 divisors (see below), whose sum is σ = 30903444. Its totient is φ = 10212640.

The previous prime is 20513783. The next prime is 20513791. The reversal of 20513786 is 68731502.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19669225 + 844561 = 4435^2 + 919^2 .

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20513783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21545 + ... + 22476.

Almost surely, 2^20513786 is an apocalyptic number.

20513786 is a deficient number, since it is larger than the sum of its proper divisors (10389658).

20513786 is a wasteful number, since it uses less digits than its factorization.

20513786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44256.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 20513786 is about 4529.2147222228. The cubic root of 20513786 is about 273.7465199755.

The spelling of 20513786 in words is "twenty million, five hundred thirteen thousand, seven hundred eighty-six".