20551216667 has 4 divisors (see below), whose sum is σ = 21052465896. Its totient is φ = 20049967440.

The previous prime is 20551216643. The next prime is 20551216729. The reversal of 20551216667 is 76661215502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 76661215502 = 2 ⋅38330607751.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20551216667 is a prime.

It is a super-3 number, since 3×20551216667³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (41), and also a Moran number because the ratio is a prime number: 501249187 = 20551216667 / (2 + 0 + 5 + 5 + 1 + 2 + 1 + 6 + 6 + 6 + 7).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20551116667) 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, 250624553 + ... + 250624634.

It is an arithmetic number, because the mean of its divisors is an integer number (5263116474).

Almost surely, 2^20551216667 is an apocalyptic number.

20551216667 is a deficient number, since it is larger than the sum of its proper divisors (501249229).

20551216667 is an equidigital number, since it uses as much as digits as its factorization.

20551216667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 501249228.

The product of its (nonzero) digits is 151200, while the sum is 41.

The spelling of 20551216667 in words is "twenty billion, five hundred fifty-one million, two hundred sixteen thousand, six hundred sixty-seven".