21345429421 has 4 divisors (see below), whose sum is σ = 21646069344. Its totient is φ = 21044789500.

The previous prime is 21345429377. The next prime is 21345429493. The reversal of 21345429421 is 12492454312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21345429421 - 2¹⁷ = 21345298349 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 (21345429821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 150319855 + ... + 150319996.

It is an arithmetic number, because the mean of its divisors is an integer number (5411517336).

Almost surely, 2^21345429421 is an apocalyptic number.

It is an amenable number.

21345429421 is a deficient number, since it is larger than the sum of its proper divisors (300639923).

21345429421 is an equidigital number, since it uses as much as digits as its factorization.

21345429421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300639922.

The product of its digits is 69120, while the sum is 37.

The spelling of 21345429421 in words is "twenty-one billion, three hundred forty-five million, four hundred twenty-nine thousand, four hundred twenty-one".