81466624 has 18 divisors (see below), whose sum is σ = 162615530. Its totient is φ = 40733184.

The previous prime is 81466603. The next prime is 81466643. The reversal of 81466624 is 42666418.

It can be written as a sum of positive squares in only one way, i.e., 63489024 + 17977600 = 7968^2 + 4240^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 158859 + ... + 159370.

Almost surely, 2^81466624 is an apocalyptic number.

It is an amenable number.

81466624 is a deficient number, since it is larger than the sum of its proper divisors (81148906).

81466624 is an equidigital number, since it uses as much as digits as its factorization.

81466624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318245 (or 318231 counting only the distinct ones).

The product of its digits is 55296, while the sum is 37.

The square root of 81466624 is about 9025.8863276689. The cubic root of 81466624 is about 433.5041304366.

It can be divided in two parts, 8146662 and 4, that added together give a triangular number (8146666 = T₄₀₃₆).

The spelling of 81466624 in words is "eighty-one million, four hundred sixty-six thousand, six hundred twenty-four".