21154201440 has 48 divisors (see below), whose sum is σ = 66635736048. Its totient is φ = 5641120256.

The previous prime is 21154201427. The next prime is 21154201441. The reversal of 21154201440 is 4410245112.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21154201440.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21154201441) 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, 22035147 + ... + 22036106.

It is an arithmetic number, because the mean of its divisors is an integer number (1388244501).

Almost surely, 2^21154201440 is an apocalyptic number.

21154201440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21154201440 is an abundant number, since it is smaller than the sum of its proper divisors (45481534608).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21154201440 is a wasteful number, since it uses less digits than its factorization.

21154201440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44071271 (or 44071263 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

Adding to 21154201440 its reverse (4410245112), we get a palindrome (25564446552).

The spelling of 21154201440 in words is "twenty-one billion, one hundred fifty-four million, two hundred one thousand, four hundred forty".