20851546 has 4 divisors (see below), whose sum is σ = 31277322. Its totient is φ = 10425772.

The previous prime is 20851541. The next prime is 20851549. The reversal of 20851546 is 64515802.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20839225 + 12321 = 4565^2 + 111^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (20851541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5212885 + ... + 5212888.

Almost surely, 2^20851546 is an apocalyptic number.

20851546 is a deficient number, since it is larger than the sum of its proper divisors (10425776).

20851546 is a wasteful number, since it uses less digits than its factorization.

20851546 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10425775.

The product of its (nonzero) digits is 9600, while the sum is 31.

The square root of 20851546 is about 4566.3493077074. The cubic root of 20851546 is about 275.2407632543.

The spelling of 20851546 in words is "twenty million, eight hundred fifty-one thousand, five hundred forty-six".