20145321421 has 4 divisors (see below), whose sum is σ = 20613817312. Its totient is φ = 19676825532.

The previous prime is 20145321403. The next prime is 20145321437. The reversal of 20145321421 is 12412354102.

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 a de Polignac number, because none of the positive numbers 2^k-20145321421 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 (20145321401) 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, 234247881 + ... + 234247966.

It is an arithmetic number, because the mean of its divisors is an integer number (5153454328).

Almost surely, 2^20145321421 is an apocalyptic number.

It is an amenable number.

20145321421 is a deficient number, since it is larger than the sum of its proper divisors (468495891).

20145321421 is an equidigital number, since it uses as much as digits as its factorization.

20145321421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468495890.

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 20145321421 its reverse (12412354102), we get a palindrome (32557675523).

The spelling of 20145321421 in words is "twenty billion, one hundred forty-five million, three hundred twenty-one thousand, four hundred twenty-one".