21444140391 has 8 divisors (see below), whose sum is σ = 30274080624. Its totient is φ = 13455146880.

The previous prime is 21444140387. The next prime is 21444140407. The reversal of 21444140391 is 19304144412.

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

It is not a de Polignac number, because 21444140391 - 2² = 21444140387 is a prime.

It is a super-3 number, since 3×21444140391³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21444140491) 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, 210236620 + ... + 210236721.

It is an arithmetic number, because the mean of its divisors is an integer number (3784260078).

Almost surely, 2^21444140391 is an apocalyptic number.

21444140391 is a deficient number, since it is larger than the sum of its proper divisors (8829940233).

21444140391 is a wasteful number, since it uses less digits than its factorization.

21444140391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 420473361.

The product of its (nonzero) digits is 13824, while the sum is 33.

The spelling of 21444140391 in words is "twenty-one billion, four hundred forty-four million, one hundred forty thousand, three hundred ninety-one".