81641534 has 12 divisors (see below), whose sum is σ = 132607656. Its totient is φ = 37680552.

The previous prime is 81641501. The next prime is 81641557. The reversal of 81641534 is 43514618.

It is a super-3 number, since 3×81641534³ (a number of 25 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81641534.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 120434 + ... + 121109.

It is an arithmetic number, because the mean of its divisors is an integer number (11050638).

Almost surely, 2^81641534 is an apocalyptic number.

81641534 is a deficient number, since it is larger than the sum of its proper divisors (50966122).

81641534 is a wasteful number, since it uses less digits than its factorization.

81641534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241571 (or 241558 counting only the distinct ones).

The product of its digits is 11520, while the sum is 32.

The square root of 81641534 is about 9035.5704855864. The cubic root of 81641534 is about 433.8141551770.

The spelling of 81641534 in words is "eighty-one million, six hundred forty-one thousand, five hundred thirty-four".