647138220 has 48 divisors (see below), whose sum is σ = 1813674240. Its totient is φ = 172409536.

The previous prime is 647138213. The next prime is 647138221. The reversal of 647138220 is 22831746.

647138220 = 25² + 26² + ... + 1247².

It is not an unprimeable number, because it can be changed into a prime (647138221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68971 + ... + 77789.

It is an arithmetic number, because the mean of its divisors is an integer number (37784880).

Almost surely, 2^647138220 is an apocalyptic number.

647138220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

647138220 is an abundant number, since it is smaller than the sum of its proper divisors (1166536020).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

647138220 is a wasteful number, since it uses less digits than its factorization.

647138220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10054 (or 10052 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 33.

The square root of 647138220 is about 25438.9115333184. The cubic root of 647138220 is about 864.9659603253.

Adding to 647138220 its reverse (22831746), we get a palindrome (669969966).

The spelling of 647138220 in words is "six hundred forty-seven million, one hundred thirty-eight thousand, two hundred twenty".