21144312021 has 8 divisors (see below), whose sum is σ = 32219904064. Its totient is φ = 12082464000.

The previous prime is 21144312017. The next prime is 21144312097. The reversal of 21144312021 is 12021344112.

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

It is not a de Polignac number, because 21144312021 - 2² = 21144312017 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 1006872001 = 21144312021 / (2 + 1 + 1 + 4 + 4 + 3 + 1 + 2 + 0 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144312221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 503435980 + ... + 503436021.

It is an arithmetic number, because the mean of its divisors is an integer number (4027488008).

Almost surely, 2^21144312021 is an apocalyptic number.

21144312021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21144312021 is a deficient number, since it is larger than the sum of its proper divisors (11075592043).

21144312021 is a wasteful number, since it uses less digits than its factorization.

21144312021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1006872011.

The product of its (nonzero) digits is 384, while the sum is 21.

Adding to 21144312021 its reverse (12021344112), we get a palindrome (33165656133).

The spelling of 21144312021 in words is "twenty-one billion, one hundred forty-four million, three hundred twelve thousand, twenty-one".