81954940909 has 8 divisors (see below), whose sum is σ = 88622114688. Its totient is φ = 75492911040.

The previous prime is 81954940897. The next prime is 81954940933. The reversal of 81954940909 is 90904945918.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81954940909 - 2¹¹ = 81954938861 is a prime.

It is a super-2 number, since 2×81954940909² (a number of 23 digits) 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 (81954944909) 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, 51285147 + ... + 51286744.

It is an arithmetic number, because the mean of its divisors is an integer number (11077764336).

Almost surely, 2^81954940909 is an apocalyptic number.

It is an amenable number.

81954940909 is a deficient number, since it is larger than the sum of its proper divisors (6667173779).

81954940909 is a wasteful number, since it uses less digits than its factorization.

81954940909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102571955.

The product of its (nonzero) digits is 4199040, while the sum is 58.

The spelling of 81954940909 in words is "eighty-one billion, nine hundred fifty-four million, nine hundred forty thousand, nine hundred nine".