81322651 has 2 divisors, whose sum is σ = 81322652. Its totient is φ = 81322650.

The previous prime is 81322613. The next prime is 81322663. The reversal of 81322651 is 15622318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81322651 - 2¹³ = 81314459 is a prime.

It is a super-2 number, since 2×81322651² = 13226747131335602, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81322601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40661325 + 40661326.

It is an arithmetic number, because the mean of its divisors is an integer number (40661326).

Almost surely, 2^81322651 is an apocalyptic number.

81322651 is a deficient number, since it is larger than the sum of its proper divisors (1).

81322651 is an equidigital number, since it uses as much as digits as its factorization.

81322651 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 28.

The square root of 81322651 is about 9017.9072405963. The cubic root of 81322651 is about 433.2486078274.

Adding to 81322651 its reverse (15622318), we get a palindrome (96944969).

The spelling of 81322651 in words is "eighty-one million, three hundred twenty-two thousand, six hundred fifty-one".