21352236421 has 4 divisors (see below), whose sum is σ = 21437305344. Its totient is φ = 21267167500.

The previous prime is 21352236383. The next prime is 21352236469. The reversal of 21352236421 is 12463225312.

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 21352236421 - 2¹³ = 21352228229 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 (21352236481) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42534085 + ... + 42534586.

It is an arithmetic number, because the mean of its divisors is an integer number (5359326336).

Almost surely, 2^21352236421 is an apocalyptic number.

It is an amenable number.

21352236421 is a deficient number, since it is larger than the sum of its proper divisors (85068923).

21352236421 is an equidigital number, since it uses as much as digits as its factorization.

21352236421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85068922.

The product of its digits is 17280, while the sum is 31.

The spelling of 21352236421 in words is "twenty-one billion, three hundred fifty-two million, two hundred thirty-six thousand, four hundred twenty-one".