71205021 has 16 divisors (see below), whose sum is σ = 105630400. Its totient is φ = 47406384.

The previous prime is 71205019. The next prime is 71205037. The reversal of 71205021 is 12050217.

It is not a de Polignac number, because 71205021 - 2¹ = 71205019 is a prime.

It is a super-2 number, since 2×71205021² = 10140310031220882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 71204985 and 71205003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71205221) 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, 27630 + ... + 30096.

It is an arithmetic number, because the mean of its divisors is an integer number (6601900).

Almost surely, 2^71205021 is an apocalyptic number.

It is an amenable number.

71205021 is a deficient number, since it is larger than the sum of its proper divisors (34425379).

71205021 is a wasteful number, since it uses less digits than its factorization.

71205021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3545 (or 3539 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 71205021 is about 8438.3067614303. The cubic root of 71205021 is about 414.4799621496.

Adding to 71205021 its reverse (12050217), we get a palindrome (83255238).

The spelling of 71205021 in words is "seventy-one million, two hundred five thousand, twenty-one".