81212101372 has 24 divisors (see below), whose sum is σ = 144551481984. Its totient is φ = 39914275632.

The previous prime is 81212101351. The next prime is 81212101379. The reversal of 81212101372 is 27310121218.

It is a self number, because there is not a number n which added to its sum of digits gives 81212101372.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81212101379) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 199288 + ... + 449599.

It is an arithmetic number, because the mean of its divisors is an integer number (6022978416).

Almost surely, 2^81212101372 is an apocalyptic number.

It is an amenable number.

81212101372 is a deficient number, since it is larger than the sum of its proper divisors (63339380612).

81212101372 is a wasteful number, since it uses less digits than its factorization.

81212101372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 649425 (or 649423 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 28.

The spelling of 81212101372 in words is "eighty-one billion, two hundred twelve million, one hundred one thousand, three hundred seventy-two".