8572781381 has 2 divisors, whose sum is σ = 8572781382. Its totient is φ = 8572781380.

The previous prime is 8572781377. The next prime is 8572781383. The reversal of 8572781381 is 1831872758.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8484252100 + 88529281 = 92110^2 + 9409^2 .

It is a cyclic number.

It is not a de Polignac number, because 8572781381 - 2² = 8572781377 is a prime.

It is a super-2 number, since 2×8572781381² (a number of 21 digits) contains 22 as substring.

Together with 8572781383, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8572781383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4286390690 + 4286390691.

It is an arithmetic number, because the mean of its divisors is an integer number (4286390691).

Almost surely, 2^8572781381 is an apocalyptic number.

It is an amenable number.

8572781381 is a deficient number, since it is larger than the sum of its proper divisors (1).

8572781381 is an equidigital number, since it uses as much as digits as its factorization.

8572781381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 752640, while the sum is 50.

The square root of 8572781381 is about 92589.3156957108. The cubic root of 8572781381 is about 2046.6358768612.

The spelling of 8572781381 in words is "eight billion, five hundred seventy-two million, seven hundred eighty-one thousand, three hundred eighty-one".