641721471 has 4 divisors (see below), whose sum is σ = 855628632. Its totient is φ = 427814312.

The previous prime is 641721449. The next prime is 641721481. The reversal of 641721471 is 174127146.

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 641721471 - 2¹³ = 641713279 is a prime.

It is a super-3 number, since 3×641721471³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641721481) 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, 106953576 + ... + 106953581.

It is an arithmetic number, because the mean of its divisors is an integer number (213907158).

Almost surely, 2^641721471 is an apocalyptic number.

641721471 is a deficient number, since it is larger than the sum of its proper divisors (213907161).

641721471 is a wasteful number, since it uses less digits than its factorization.

641721471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213907160.

The product of its digits is 9408, while the sum is 33.

The square root of 641721471 is about 25332.2219909743. The cubic root of 641721471 is about 862.5458502826.

The spelling of 641721471 in words is "six hundred forty-one million, seven hundred twenty-one thousand, four hundred seventy-one".