20867711251 has 4 divisors (see below), whose sum is σ = 20872764432. Its totient is φ = 20862658072.

The previous prime is 20867711237. The next prime is 20867711261. The reversal of 20867711251 is 15211776802.

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

It is a cyclic number.

It is not a de Polignac number, because 20867711251 - 2⁹ = 20867710739 is a prime.

It is a super-2 number, since 2×20867711251² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20867711261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2520391 + ... + 2528656.

It is an arithmetic number, because the mean of its divisors is an integer number (5218191108).

Almost surely, 2^20867711251 is an apocalyptic number.

20867711251 is a deficient number, since it is larger than the sum of its proper divisors (5053181).

20867711251 is an equidigital number, since it uses as much as digits as its factorization.

20867711251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5053180.

The product of its (nonzero) digits is 47040, while the sum is 40.

The spelling of 20867711251 in words is "twenty billion, eight hundred sixty-seven million, seven hundred eleven thousand, two hundred fifty-one".