81937419 has 8 divisors (see below), whose sum is σ = 109768512. Its totient is φ = 54365640.

The previous prime is 81937411. The next prime is 81937439. The reversal of 81937419 is 91473918.

It is a happy number.

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

It is not a de Polignac number, because 81937419 - 2³ = 81937411 is a prime.

It is a super-2 number, since 2×81937419² = 13427481264763122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81937411) 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, 64089 + ... + 65354.

It is an arithmetic number, because the mean of its divisors is an integer number (13721064).

Almost surely, 2^81937419 is an apocalyptic number.

81937419 is a deficient number, since it is larger than the sum of its proper divisors (27831093).

81937419 is a wasteful number, since it uses less digits than its factorization.

81937419 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129657.

The product of its digits is 54432, while the sum is 42.

The square root of 81937419 is about 9051.9290209325. The cubic root of 81937419 is about 434.3375993125.

The spelling of 81937419 in words is "eighty-one million, nine hundred thirty-seven thousand, four hundred nineteen".