71215021 has 8 divisors (see below), whose sum is σ = 75042080. Its totient is φ = 67395888.

The previous prime is 71215003. The next prime is 71215033. The reversal of 71215021 is 12051217.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 71215021 - 2¹⁹ = 70690733 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 71215021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71215321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29170 + ... + 31516.

It is an arithmetic number, because the mean of its divisors is an integer number (9380260).

Almost surely, 2^71215021 is an apocalyptic number.

It is an amenable number.

71215021 is a deficient number, since it is larger than the sum of its proper divisors (3827059).

71215021 is a wasteful number, since it uses less digits than its factorization.

71215021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3963.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 71215021 is about 8438.8992765645. The cubic root of 71215021 is about 414.4993643656.

Adding to 71215021 its reverse (12051217), we get a palindrome (83266238).

The spelling of 71215021 in words is "seventy-one million, two hundred fifteen thousand, twenty-one".