81684954 has 24 divisors (see below), whose sum is σ = 190598772. Its totient is φ = 25133760.

The previous prime is 81684947. The next prime is 81684989. The reversal of 81684954 is 45948618.

It can be written as a sum of positive squares in 2 ways, for example, as 72846225 + 8838729 = 8535^2 + 2973^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 174307 + ... + 174774.

Almost surely, 2^81684954 is an apocalyptic number.

81684954 is an abundant number, since it is smaller than the sum of its proper divisors (108913818).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81684954 is a wasteful number, since it uses less digits than its factorization.

81684954 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 349102 (or 349099 counting only the distinct ones).

The product of its digits is 276480, while the sum is 45.

The square root of 81684954 is about 9037.9728921921. The cubic root of 81684954 is about 433.8910477071.

It can be divided in two parts, 81 and 684954, that added together give a triangular number (685035 = T₁₁₇₀).

The spelling of 81684954 in words is "eighty-one million, six hundred eighty-four thousand, nine hundred fifty-four".