641726549 has 4 divisors (see below), whose sum is σ = 643917036. Its totient is φ = 639536064.

The previous prime is 641726543. The next prime is 641726621. The reversal of 641726549 is 945627146.

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 610979524 + 30747025 = 24718^2 + 5545^2 .

It is a cyclic number.

It is not a de Polignac number, because 641726549 - 2¹² = 641722453 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641726543) 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, 1094804 + ... + 1095389.

It is an arithmetic number, because the mean of its divisors is an integer number (160979259).

Almost surely, 2^641726549 is an apocalyptic number.

It is an amenable number.

641726549 is a deficient number, since it is larger than the sum of its proper divisors (2190487).

641726549 is a wasteful number, since it uses less digits than its factorization.

641726549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2190486.

The product of its digits is 362880, while the sum is 44.

The square root of 641726549 is about 25332.3222188571. The cubic root of 641726549 is about 862.5481254110.

The spelling of 641726549 in words is "six hundred forty-one million, seven hundred twenty-six thousand, five hundred forty-nine".