647238399 has 32 divisors (see below), whose sum is σ = 934053120. Its totient is φ = 397189632.

The previous prime is 647238379. The next prime is 647238407. The reversal of 647238399 is 993832746.

It is not a de Polignac number, because 647238399 - 2²¹ = 645141247 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a Sastry number since concatenated with its successor gives a square.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647238329) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 452217 + ... + 453645.

It is an arithmetic number, because the mean of its divisors is an integer number (29189160).

Almost surely, 2^647238399 is an apocalyptic number.

647238399 is a deficient number, since it is larger than the sum of its proper divisors (286814721).

647238399 is a wasteful number, since it uses less digits than its factorization.

647238399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1639.

The product of its digits is 1959552, while the sum is 51.

The square root of 647238399 is about 25440.8804682542. The cubic root of 647238399 is about 865.0105911586.

The spelling of 647238399 in words is "six hundred forty-seven million, two hundred thirty-eight thousand, three hundred ninety-nine".