644737151242 has 16 divisors (see below), whose sum is σ = 1009475721792. Its totient is φ = 308254186240.

The previous prime is 644737151197. The next prime is 644737151273. The reversal of 644737151242 is 242151737446.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a junction number, because it is equal to n+sod(n) for n = 644737151192 and 644737151201.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2089684 + ... + 2378287.

It is an arithmetic number, because the mean of its divisors is an integer number (63092232612).

Almost surely, 2^644737151242 is an apocalyptic number.

644737151242 is a deficient number, since it is larger than the sum of its proper divisors (364738570550).

644737151242 is a wasteful number, since it uses less digits than its factorization.

644737151242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4471133.

The product of its digits is 1128960, while the sum is 46.

Adding to 644737151242 its reverse (242151737446), we get a palindrome (886888888688).

The spelling of 644737151242 in words is "six hundred forty-four billion, seven hundred thirty-seven million, one hundred fifty-one thousand, two hundred forty-two".