81764619 has 32 divisors (see below), whose sum is σ = 119750400. Its totient is φ = 49443840.

The previous prime is 81764597. The next prime is 81764621. The reversal of 81764619 is 91646718.

It is not a de Polignac number, because 81764619 - 2⁷ = 81764491 is a prime.

It is a super-2 number, since 2×81764619² = 13370905840430322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81764119) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 137587 + ... + 138179.

It is an arithmetic number, because the mean of its divisors is an integer number (3742200).

Almost surely, 2^81764619 is an apocalyptic number.

81764619 is a deficient number, since it is larger than the sum of its proper divisors (37985781).

81764619 is a wasteful number, since it uses less digits than its factorization.

81764619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 715.

The product of its digits is 72576, while the sum is 42.

The square root of 81764619 is about 9042.3790564209. The cubic root of 81764619 is about 434.0320557209.

The spelling of 81764619 in words is "eighty-one million, seven hundred sixty-four thousand, six hundred nineteen".