71978240 has 72 divisors (see below), whose sum is σ = 175828968. Its totient is φ = 28221440.

The previous prime is 71978239. The next prime is 71978287. The reversal of 71978240 is 4287917.

It can be written as a sum of positive squares in 4 ways, for example, as 17572864 + 54405376 = 4192^2 + 7376^2 .

It is a junction number, because it is equal to n+sod(n) for n = 71978194 and 71978203.

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, 67310 + ... + 68370.

It is an arithmetic number, because the mean of its divisors is an integer number (2442069).

Almost surely, 2^71978240 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 71978240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87914484).

71978240 is an abundant number, since it is smaller than the sum of its proper divisors (103850728).

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

71978240 is a wasteful number, since it uses less digits than its factorization.

71978240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1135 (or 1121 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 71978240 is about 8483.9990570485. Note that the first 3 decimals coincide. The cubic root of 71978240 is about 415.9748505506.

The spelling of 71978240 in words is "seventy-one million, nine hundred seventy-eight thousand, two hundred forty".