644537463574 has 4 divisors (see below), whose sum is σ = 966806195364. Its totient is φ = 322268731786.

The previous prime is 644537463541. The next prime is 644537463589. The reversal of 644537463574 is 475364735446.

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: 475364735446 = 2 ⋅237682367723.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161134365892 + ... + 161134365895.

It is an arithmetic number, because the mean of its divisors is an integer number (241701548841).

Almost surely, 2^644537463574 is an apocalyptic number.

644537463574 is a deficient number, since it is larger than the sum of its proper divisors (322268731790).

644537463574 is a wasteful number, since it uses less digits than its factorization.

644537463574 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322268731789.

The product of its digits is 101606400, while the sum is 58.

The spelling of 644537463574 in words is "six hundred forty-four billion, five hundred thirty-seven million, four hundred sixty-three thousand, five hundred seventy-four".