21212420591 has 8 divisors (see below), whose sum is σ = 23098825200. Its totient is φ = 19403012160.

The previous prime is 21212420573. The next prime is 21212420617. The reversal of 21212420591 is 19502421212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21212420591 - 2⁶ = 21212420527 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212420291) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19248470 + ... + 19249571.

It is an arithmetic number, because the mean of its divisors is an integer number (2887353150).

Almost surely, 2^21212420591 is an apocalyptic number.

21212420591 is a deficient number, since it is larger than the sum of its proper divisors (1886404609).

21212420591 is a wasteful number, since it uses less digits than its factorization.

21212420591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38498089.

The product of its (nonzero) digits is 2880, while the sum is 29.

The spelling of 21212420591 in words is "twenty-one billion, two hundred twelve million, four hundred twenty thousand, five hundred ninety-one".