21401342452 has 24 divisors (see below), whose sum is σ = 42860646080. Its totient is φ = 9159583680.

The previous prime is 21401342399. The next prime is 21401342453. The reversal of 21401342452 is 25424310412.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a self number, because there is not a number n which added to its sum of digits gives 21401342452.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21401342453) 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, 496449 + ... + 537832.

Almost surely, 2^21401342452 is an apocalyptic number.

It is an amenable number.

21401342452 is an abundant number, since it is smaller than the sum of its proper divisors (21459303628).

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

21401342452 is a wasteful number, since it uses less digits than its factorization.

21401342452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1035031 (or 1035029 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 28.

Adding to 21401342452 its reverse (25424310412), we get a palindrome (46825652864).

The spelling of 21401342452 in words is "twenty-one billion, four hundred one million, three hundred forty-two thousand, four hundred fifty-two".