71221566 has 32 divisors (see below), whose sum is σ = 154441728. Its totient is φ = 21765600.

The previous prime is 71221541. The next prime is 71221567. The reversal of 71221566 is 66512217.

It is a super-2 number, since 2×71221566² = 10145022926984712, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71221567) 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, 8755 + ... + 14801.

It is an arithmetic number, because the mean of its divisors is an integer number (4826304).

Almost surely, 2^71221566 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 71221566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77220864).

71221566 is an abundant number, since it is smaller than the sum of its proper divisors (83220162).

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

71221566 is a wasteful number, since it uses less digits than its factorization.

71221566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6216.

The product of its digits is 5040, while the sum is 30.

The square root of 71221566 is about 8439.2870551961. The cubic root of 71221566 is about 414.5120621326.

The spelling of 71221566 in words is "seventy-one million, two hundred twenty-one thousand, five hundred sixty-six".