20716217451 has 10 divisors (see below), whose sum is σ = 30946448412. Its totient is φ = 13810811580.

The previous prime is 20716217447. The next prime is 20716217491. The reversal of 20716217451 is 15471261702.

20716217451 is a `hidden beast` number, since 20 + 7 + 1 + 621 + 7 + 4 + 5 + 1 = 666.

It is not a de Polignac number, because 20716217451 - 2² = 20716217447 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20716217491) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 127877805 + ... + 127877966.

Almost surely, 2^20716217451 is an apocalyptic number.

20716217451 is a deficient number, since it is larger than the sum of its proper divisors (10230230961).

20716217451 is an equidigital number, since it uses as much as digits as its factorization.

20716217451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255755783 (or 255755774 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

The spelling of 20716217451 in words is "twenty billion, seven hundred sixteen million, two hundred seventeen thousand, four hundred fifty-one".