8187564421 has 2 divisors, whose sum is σ = 8187564422. Its totient is φ = 8187564420.

The previous prime is 8187564383. The next prime is 8187564467. The reversal of 8187564421 is 1244657818.

It is an a-pointer prime, because the next prime (8187564467) can be obtained adding 8187564421 to its sum of digits (46).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6676687521 + 1510876900 = 81711^2 + 38870^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8187564421 is a prime.

It is a super-2 number, since 2×8187564421² (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 (8187564521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4093782210 + 4093782211.

It is an arithmetic number, because the mean of its divisors is an integer number (4093782211).

Almost surely, 2^8187564421 is an apocalyptic number.

It is an amenable number.

8187564421 is a deficient number, since it is larger than the sum of its proper divisors (1).

8187564421 is an equidigital number, since it uses as much as digits as its factorization.

8187564421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 430080, while the sum is 46.

The square root of 8187564421 is about 90485.1613304635. The cubic root of 8187564421 is about 2015.5097808548.

The spelling of 8187564421 in words is "eight billion, one hundred eighty-seven million, five hundred sixty-four thousand, four hundred twenty-one".