71220640 has 96 divisors (see below), whose sum is σ = 176795136. Its totient is φ = 27079680.

The previous prime is 71220637. The next prime is 71220641. The reversal of 71220640 is 4602217.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71220641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 411594 + ... + 411766.

It is an arithmetic number, because the mean of its divisors is an integer number (1841616).

Almost surely, 2^71220640 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 71220640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88397568).

71220640 is an abundant number, since it is smaller than the sum of its proper divisors (105574496).

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

71220640 is a wasteful number, since it uses less digits than its factorization.

71220640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302 (or 294 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 71220640 is about 8439.2321925635. The cubic root of 71220640 is about 414.5102656738.

Adding to 71220640 its reverse (4602217), we get a palindrome (75822857).

The spelling of 71220640 in words is "seventy-one million, two hundred twenty thousand, six hundred forty".