64849821637 has 4 divisors (see below), whose sum is σ = 64861323436. Its totient is φ = 64838319840.

The previous prime is 64849821577. The next prime is 64849821643. The reversal of 64849821637 is 73612894846.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 29204759236 + 35645062401 = 170894^2 + 188799^2 .

It is a cyclic number.

It is not a de Polignac number, because 64849821637 - 2¹⁹ = 64849297349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64849881637) 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, 5742438 + ... + 5753719.

It is an arithmetic number, because the mean of its divisors is an integer number (16215330859).

Almost surely, 2^64849821637 is an apocalyptic number.

It is an amenable number.

64849821637 is a deficient number, since it is larger than the sum of its proper divisors (11501799).

64849821637 is a wasteful number, since it uses less digits than its factorization.

64849821637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11501798.

The product of its digits is 13934592, while the sum is 58.

The spelling of 64849821637 in words is "sixty-four billion, eight hundred forty-nine million, eight hundred twenty-one thousand, six hundred thirty-seven".