71220865 has 4 divisors (see below), whose sum is σ = 85465044. Its totient is φ = 56976688.

The previous prime is 71220859. The next prime is 71220883. The reversal of 71220865 is 56802217.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11498881 + 59721984 = 3391^2 + 7728^2 .

It is a cyclic number.

It is not a de Polignac number, because 71220865 - 2⁵ = 71220833 is a prime.

It is a super-2 number, since 2×71220865² = 10144823222696450, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7122082 + ... + 7122091.

It is an arithmetic number, because the mean of its divisors is an integer number (21366261).

Almost surely, 2^71220865 is an apocalyptic number.

It is an amenable number.

71220865 is a deficient number, since it is larger than the sum of its proper divisors (14244179).

71220865 is a wasteful number, since it uses less digits than its factorization.

71220865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14244178.

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 71220865 is about 8439.2455231496. The cubic root of 71220865 is about 414.5107021798.

The spelling of 71220865 in words is "seventy-one million, two hundred twenty thousand, eight hundred sixty-five".