71891820 has 576 divisors, whose sum is σ = 321753600. Its totient is φ = 13063680.

The previous prime is 71891803. The next prime is 71891849. The reversal of 71891820 is 2819817.

It is a super-3 number, since 3×71891820³ (a number of 25 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 3783771 + ... + 3783789.

It is an arithmetic number, because the mean of its divisors is an integer number (558600).

Almost surely, 2^71891820 is an apocalyptic number.

71891820 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 71891820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160876800).

71891820 is an abundant number, since it is smaller than the sum of its proper divisors (249861780).

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

71891820 is a wasteful number, since it uses less digits than its factorization.

71891820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 71891820 is about 8478.9044103587. The cubic root of 71891820 is about 415.8083051091.

It can be divided in two parts, 7189 and 1820, that added together give a palindrome (9009).

The spelling of 71891820 in words is "seventy-one million, eight hundred ninety-one thousand, eight hundred twenty".