71681820 has 96 divisors (see below), whose sum is σ = 231748608. Its totient is φ = 16215552.

The previous prime is 71681807. The next prime is 71681837. The reversal of 71681820 is 2818617.

It is a happy number.

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, 42432 + ... + 44088.

It is an arithmetic number, because the mean of its divisors is an integer number (2414048).

Almost surely, 2^71681820 is an apocalyptic number.

71681820 is a gapful number since it is divisible by the number (70) 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 71681820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (115874304).

71681820 is an abundant number, since it is smaller than the sum of its proper divisors (160066788).

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

71681820 is a wasteful number, since it uses less digits than its factorization.

71681820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1779 (or 1777 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 33.

The square root of 71681820 is about 8466.5116783714. The cubic root of 71681820 is about 415.4030438695.

The spelling of 71681820 in words is "seventy-one million, six hundred eighty-one thousand, eight hundred twenty".