647642071 has 4 divisors (see below), whose sum is σ = 648692352. Its totient is φ = 646591792.

The previous prime is 647642069. The next prime is 647642077. The reversal of 647642071 is 170246746.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 170246746 = 2 ⋅85123373.

It is a cyclic number.

It is not a de Polignac number, because 647642071 - 2¹ = 647642069 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 647642071.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647642077) 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, 524215 + ... + 525448.

It is an arithmetic number, because the mean of its divisors is an integer number (162173088).

Almost surely, 2^647642071 is an apocalyptic number.

647642071 is a deficient number, since it is larger than the sum of its proper divisors (1050281).

647642071 is a wasteful number, since it uses less digits than its factorization.

647642071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1050280.

The product of its (nonzero) digits is 56448, while the sum is 37.

The square root of 647642071 is about 25448.8127620917. The cubic root of 647642071 is about 865.1903847701.

The spelling of 647642071 in words is "six hundred forty-seven million, six hundred forty-two thousand, seventy-one".