71645649 has 4 divisors (see below), whose sum is σ = 95527536. Its totient is φ = 47763764.

The previous prime is 71645641. The next prime is 71645669. The reversal of 71645649 is 94654617.

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: 94654617 = 3 ⋅31551539.

It is a cyclic number.

It is not a de Polignac number, because 71645649 - 2³ = 71645641 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 71645649.

It is not an unprimeable number, because it can be changed into a prime (71645641) 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, 11940939 + ... + 11940944.

It is an arithmetic number, because the mean of its divisors is an integer number (23881884).

Almost surely, 2^71645649 is an apocalyptic number.

It is an amenable number.

71645649 is a deficient number, since it is larger than the sum of its proper divisors (23881887).

71645649 is a wasteful number, since it uses less digits than its factorization.

71645649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23881886.

The product of its digits is 181440, while the sum is 42.

The square root of 71645649 is about 8464.3752870487. The cubic root of 71645649 is about 415.3331606387. Note that the first 3 decimals are identical.

The spelling of 71645649 in words is "seventy-one million, six hundred forty-five thousand, six hundred forty-nine".