20807904281 has 4 divisors (see below), whose sum is σ = 20959786932. Its totient is φ = 20656021632.

The previous prime is 20807904263. The next prime is 20807904311. The reversal of 20807904281 is 18240970802.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4663660681 + 16144243600 = 68291^2 + 127060^2 .

It is a cyclic number.

It is not a de Polignac number, because 20807904281 - 2¹⁸ = 20807642137 is a prime.

It is a super-2 number, since 2×20807904281² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20807904581) 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, 75941120 + ... + 75941393.

It is an arithmetic number, because the mean of its divisors is an integer number (5239946733).

Almost surely, 2^20807904281 is an apocalyptic number.

It is an amenable number.

20807904281 is a deficient number, since it is larger than the sum of its proper divisors (151882651).

20807904281 is a wasteful number, since it uses less digits than its factorization.

20807904281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151882650.

The product of its (nonzero) digits is 64512, while the sum is 41.

The spelling of 20807904281 in words is "twenty billion, eight hundred seven million, nine hundred four thousand, two hundred eighty-one".