81473520 has 160 divisors (see below), whose sum is σ = 281767680. Its totient is φ = 19353600.

The previous prime is 81473479. The next prime is 81473551. The reversal of 81473520 is 2537418.

It is a super-2 number, since 2×81473520² = 13275868922380800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 76995 + ... + 78045.

It is an arithmetic number, because the mean of its divisors is an integer number (1761048).

Almost surely, 2^81473520 is an apocalyptic number.

81473520 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81473520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140883840).

81473520 is an abundant number, since it is smaller than the sum of its proper divisors (200294160).

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

81473520 is a wasteful number, since it uses less digits than its factorization.

81473520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1103 (or 1097 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 81473520 is about 9026.2683319299. The cubic root of 81473520 is about 433.5163618675.

The spelling of 81473520 in words is "eighty-one million, four hundred seventy-three thousand, five hundred twenty".