71521720 has 96 divisors (see below), whose sum is σ = 179042400. Its totient is φ = 25659392.

The previous prime is 71521717. The next prime is 71521727. The reversal of 71521720 is 2712517.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71521727) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 265746 + ... + 266014.

It is an arithmetic number, because the mean of its divisors is an integer number (1865025).

Almost surely, 2^71521720 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 71521720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89521200).

71521720 is an abundant number, since it is smaller than the sum of its proper divisors (107520680).

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

71521720 is a wasteful number, since it uses less digits than its factorization.

71521720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337 (or 316 counting only the distinct ones).

The product of its (nonzero) digits is 980, while the sum is 25.

The square root of 71521720 is about 8457.0514956455. The cubic root of 71521720 is about 415.0935483695.

The spelling of 71521720 in words is "seventy-one million, five hundred twenty-one thousand, seven hundred twenty".