82120451781 has 16 divisors (see below), whose sum is σ = 110013894144. Its totient is φ = 54487118784.

The previous prime is 82120451773. The next prime is 82120451789. The reversal of 82120451781 is 18715402128.

It is an interprime number because it is at equal distance from previous prime (82120451773) and next prime (82120451789).

It is not a de Polignac number, because 82120451781 - 2³ = 82120451773 is a prime.

It is a super-2 number, since 2×82120451781² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82120451789) 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, 2927635 + ... + 2955551.

It is an arithmetic number, because the mean of its divisors is an integer number (6875868384).

Almost surely, 2^82120451781 is an apocalyptic number.

It is an amenable number.

82120451781 is a deficient number, since it is larger than the sum of its proper divisors (27893442363).

82120451781 is a wasteful number, since it uses less digits than its factorization.

82120451781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32540.

The product of its (nonzero) digits is 35840, while the sum is 39.

The spelling of 82120451781 in words is "eighty-two billion, one hundred twenty million, four hundred fifty-one thousand, seven hundred eighty-one".