81484440 has 32 divisors (see below), whose sum is σ = 244453680. Its totient is φ = 21729152.

The previous prime is 81484427. The next prime is 81484453. The reversal of 81484440 is 4448418.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81484427) and next prime (81484453).

It is a super-2 number, since 2×81484440² = 13279427924227200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 339399 + ... + 339638.

Almost surely, 2^81484440 is an apocalyptic number.

It is an amenable number.

81484440 is an abundant number, since it is smaller than the sum of its proper divisors (162969240).

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

81484440 is a wasteful number, since it uses less digits than its factorization.

81484440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 679051 (or 679047 counting only the distinct ones).

The product of its (nonzero) digits is 16384, while the sum is 33.

The square root of 81484440 is about 9026.8732128019. The cubic root of 81484440 is about 433.5357292529.

The spelling of 81484440 in words is "eighty-one million, four hundred eighty-four thousand, four hundred forty".