81155419 has 4 divisors (see below), whose sum is σ = 81959040. Its totient is φ = 80351800.

The previous prime is 81155411. The next prime is 81155423. The reversal of 81155419 is 91455118.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81155419 - 2³ = 81155411 is a prime.

It is a super-2 number, since 2×81155419² = 13172404066131122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81155411) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 401659 + ... + 401860.

It is an arithmetic number, because the mean of its divisors is an integer number (20489760).

Almost surely, 2^81155419 is an apocalyptic number.

81155419 is a deficient number, since it is larger than the sum of its proper divisors (803621).

81155419 is a wasteful number, since it uses less digits than its factorization.

81155419 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 803620.

The product of its digits is 7200, while the sum is 34.

The square root of 81155419 is about 9008.6302510426. The cubic root of 81155419 is about 432.9514263686.

The spelling of 81155419 in words is "eighty-one million, one hundred fifty-five thousand, four hundred nineteen".