81212719 has 16 divisors (see below), whose sum is σ = 95060992. Its totient is φ = 67946688.

The previous prime is 81212717. The next prime is 81212737. The reversal of 81212719 is 91721218.

It is a cyclic number.

It is not a de Polignac number, because 81212719 - 2¹ = 81212717 is a prime.

It is a super-2 number, since 2×81212719² = 13191011454745922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81212713) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51862 + ... + 53404.

It is an arithmetic number, because the mean of its divisors is an integer number (5941312).

Almost surely, 2^81212719 is an apocalyptic number.

81212719 is a deficient number, since it is larger than the sum of its proper divisors (13848273).

81212719 is a wasteful number, since it uses less digits than its factorization.

81212719 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1726.

The product of its digits is 2016, while the sum is 31.

The square root of 81212719 is about 9011.8099735847. The cubic root of 81212719 is about 433.0532978998.

It can be divided in two parts, 812 and 12719, that added together give a palindrome (13531).

The spelling of 81212719 in words is "eighty-one million, two hundred twelve thousand, seven hundred nineteen".