21051113421 has 8 divisors (see below), whose sum is σ = 30227239840. Its totient is φ = 12954531312.

The previous prime is 21051113417. The next prime is 21051113437. The reversal of 21051113421 is 12431115012.

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

It is not a de Polignac number, because 21051113421 - 2² = 21051113417 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 (21051113221) 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, 269886031 + ... + 269886108.

It is an arithmetic number, because the mean of its divisors is an integer number (3778404980).

Almost surely, 2^21051113421 is an apocalyptic number.

It is an amenable number.

21051113421 is a deficient number, since it is larger than the sum of its proper divisors (9176126419).

21051113421 is a wasteful number, since it uses less digits than its factorization.

21051113421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 539772155.

The product of its (nonzero) digits is 240, while the sum is 21.

Adding to 21051113421 its reverse (12431115012), we get a palindrome (33482228433).

The spelling of 21051113421 in words is "twenty-one billion, fifty-one million, one hundred thirteen thousand, four hundred twenty-one".