647225818 has 4 divisors (see below), whose sum is σ = 970838730. Its totient is φ = 323612908.

The previous prime is 647225797. The next prime is 647225827. The reversal of 647225818 is 818522746.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 818522746 = 2 ⋅409261373.

It can be written as a sum of positive squares in only one way, i.e., 622851849 + 24373969 = 24957^2 + 4937^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161806453 + ... + 161806456.

Almost surely, 2^647225818 is an apocalyptic number.

647225818 is a deficient number, since it is larger than the sum of its proper divisors (323612912).

647225818 is a wasteful number, since it uses less digits than its factorization.

647225818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323612911.

The product of its digits is 215040, while the sum is 43.

The square root of 647225818 is about 25440.6332075285. The cubic root of 647225818 is about 865.0049864392.

The spelling of 647225818 in words is "six hundred forty-seven million, two hundred twenty-five thousand, eight hundred eighteen".