71253561 has 4 divisors (see below), whose sum is σ = 95004752. Its totient is φ = 47502372.

The previous prime is 71253557. The next prime is 71253569. The reversal of 71253561 is 16535217.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16535217 = 3 ⋅5511739.

It is not a de Polignac number, because 71253561 - 2² = 71253557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71253569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11875591 + ... + 11875596.

It is an arithmetic number, because the mean of its divisors is an integer number (23751188).

Almost surely, 2^71253561 is an apocalyptic number.

It is an amenable number.

71253561 is a deficient number, since it is larger than the sum of its proper divisors (23751191).

71253561 is a wasteful number, since it uses less digits than its factorization.

71253561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23751190.

The product of its digits is 6300, while the sum is 30.

The square root of 71253561 is about 8441.1824408669. The cubic root of 71253561 is about 414.5741235218.

Adding to 71253561 its reverse (16535217), we get a palindrome (87788778).

The spelling of 71253561 in words is "seventy-one million, two hundred fifty-three thousand, five hundred sixty-one".