81214298781 has 48 divisors (see below), whose sum is σ = 145499768640. Its totient is φ = 39707512320.

The previous prime is 81214298777. The next prime is 81214298807. The reversal of 81214298781 is 18789241218.

It is not a de Polignac number, because 81214298781 - 2² = 81214298777 is a prime.

It is a super-2 number, since 2×81214298781² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81214298761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1449726 + ... + 1504703.

It is an arithmetic number, because the mean of its divisors is an integer number (3031245180).

Almost surely, 2^81214298781 is an apocalyptic number.

It is an amenable number.

81214298781 is a deficient number, since it is larger than the sum of its proper divisors (64285469859).

81214298781 is a wasteful number, since it uses less digits than its factorization.

81214298781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2954474 (or 2954467 counting only the distinct ones).

The product of its digits is 516096, while the sum is 51.

The spelling of 81214298781 in words is "eighty-one billion, two hundred fourteen million, two hundred ninety-eight thousand, seven hundred eighty-one".