648138787 has 4 divisors (see below), whose sum is σ = 686264616. Its totient is φ = 610012960.

The previous prime is 648138763. The next prime is 648138823. The reversal of 648138787 is 787831846.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 648138787 - 2²⁷ = 513921059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (648138587) 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, 19062889 + ... + 19062922.

It is an arithmetic number, because the mean of its divisors is an integer number (171566154).

Almost surely, 2^648138787 is an apocalyptic number.

648138787 is a deficient number, since it is larger than the sum of its proper divisors (38125829).

648138787 is a wasteful number, since it uses less digits than its factorization.

648138787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38125828.

The product of its digits is 1806336, while the sum is 52.

The square root of 648138787 is about 25458.5700109020. The cubic root of 648138787 is about 865.4115172469.

The spelling of 648138787 in words is "six hundred forty-eight million, one hundred thirty-eight thousand, seven hundred eighty-seven".