20078972581 has 2 divisors, whose sum is σ = 20078972582. Its totient is φ = 20078972580.

The previous prime is 20078972569. The next prime is 20078972611. The reversal of 20078972581 is 18527987002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20009517025 + 69455556 = 141455^2 + 8334^2 .

It is a cyclic number.

It is not a de Polignac number, because 20078972581 - 2¹⁷ = 20078841509 is a prime.

It is a super-2 number, since 2×20078972581² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20078952581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10039486290 + 10039486291.

It is an arithmetic number, because the mean of its divisors is an integer number (10039486291).

Almost surely, 2^20078972581 is an apocalyptic number.

It is an amenable number.

20078972581 is a deficient number, since it is larger than the sum of its proper divisors (1).

20078972581 is an equidigital number, since it uses as much as digits as its factorization.

20078972581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 564480, while the sum is 49.

The spelling of 20078972581 in words is "twenty billion, seventy-eight million, nine hundred seventy-two thousand, five hundred eighty-one".