71880021 has 32 divisors (see below), whose sum is σ = 113980800. Its totient is φ = 44634240.

The previous prime is 71879989. The next prime is 71880023. The reversal of 71880021 is 12008817.

It is not a de Polignac number, because 71880021 - 2⁵ = 71879989 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71880023) 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, 30145 + ... + 32441.

It is an arithmetic number, because the mean of its divisors is an integer number (3561900).

Almost surely, 2^71880021 is an apocalyptic number.

It is an amenable number.

71880021 is a deficient number, since it is larger than the sum of its proper divisors (42100779).

71880021 is a wasteful number, since it uses less digits than its factorization.

71880021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2386 (or 2380 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 27.

The square root of 71880021 is about 8478.2085961599. The cubic root of 71880021 is about 415.7855561574.

Adding to 71880021 its reverse (12008817), we get a palindrome (83888838).

The spelling of 71880021 in words is "seventy-one million, eight hundred eighty thousand, twenty-one".