81212697 has 12 divisors (see below), whose sum is σ = 117613860. Its totient is φ = 54000288.

The previous prime is 81212693. The next prime is 81212699. The reversal of 81212697 is 79621218.

It can be written as a sum of positive squares in 2 ways, for example, as 7750656 + 73462041 = 2784^2 + 8571^2 .

It is not a de Polignac number, because 81212697 - 2² = 81212693 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81212693) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8098 + ... + 15099.

It is an arithmetic number, because the mean of its divisors is an integer number (9801155).

Almost surely, 2^81212697 is an apocalyptic number.

It is an amenable number.

81212697 is a deficient number, since it is larger than the sum of its proper divisors (36401163).

81212697 is a wasteful number, since it uses less digits than its factorization.

81212697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23592 (or 23589 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 81212697 is about 9011.8087529641. The cubic root of 81212697 is about 433.0532587960.

The spelling of 81212697 in words is "eighty-one million, two hundred twelve thousand, six hundred ninety-seven".