71640420 has 96 divisors (see below), whose sum is σ = 207277056. Its totient is φ = 18480000.

The previous prime is 71640419. The next prime is 71640421. The reversal of 71640420 is 2404617.

It is an interprime number because it is at equal distance from previous prime (71640419) and next prime (71640421).

It is not an unprimeable number, because it can be changed into a prime (71640421) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 285295 + ... + 285545.

It is an arithmetic number, because the mean of its divisors is an integer number (2159136).

Almost surely, 2^71640420 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 71640420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103638528).

71640420 is an abundant number, since it is smaller than the sum of its proper divisors (135636636).

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

71640420 is a wasteful number, since it uses less digits than its factorization.

71640420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 401 (or 399 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 71640420 is about 8464.0663986053. The cubic root of 71640420 is about 415.3230561408.

The spelling of 71640420 in words is "seventy-one million, six hundred forty thousand, four hundred twenty".