8021715381 has 24 divisors (see below), whose sum is σ = 11675403480. Its totient is φ = 5307088896.

The previous prime is 8021715347. The next prime is 8021715389. The reversal of 8021715381 is 1835171208.

It can be written as a sum of positive squares in 4 ways, for example, as 3238748100 + 4782967281 = 56910^2 + 69159^2 .

It is not a de Polignac number, because 8021715381 - 2⁷ = 8021715253 is a prime.

It is a super-2 number, since 2×8021715381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8021715389) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 893925 + ... + 902853.

It is an arithmetic number, because the mean of its divisors is an integer number (486475145).

Almost surely, 2^8021715381 is an apocalyptic number.

It is an amenable number.

8021715381 is a deficient number, since it is larger than the sum of its proper divisors (3653688099).

8021715381 is a wasteful number, since it uses less digits than its factorization.

8021715381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9685 (or 9682 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 36.

The square root of 8021715381 is about 89564.0295040369. The cubic root of 8021715381 is about 2001.8079801946.

Adding to 8021715381 its reverse (1835171208), we get a palindrome (9856886589).

The spelling of 8021715381 in words is "eight billion, twenty-one million, seven hundred fifteen thousand, three hundred eighty-one".