71621609 has 4 divisors (see below), whose sum is σ = 74735616. Its totient is φ = 68507604.

The previous prime is 71621591. The next prime is 71621623. The reversal of 71621609 is 90612617.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 71621609 - 2¹⁶ = 71556073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71621699) 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, 1556969 + ... + 1557014.

It is an arithmetic number, because the mean of its divisors is an integer number (18683904).

Almost surely, 2^71621609 is an apocalyptic number.

It is an amenable number.

71621609 is a deficient number, since it is larger than the sum of its proper divisors (3114007).

71621609 is a wasteful number, since it uses less digits than its factorization.

71621609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3114006.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 71621609 is about 8462.9550985457. The cubic root of 71621609 is about 415.2867017759.

The spelling of 71621609 in words is "seventy-one million, six hundred twenty-one thousand, six hundred nine".