15432120021 has 4 divisors (see below), whose sum is σ = 20576160032. Its totient is φ = 10288080012.

The previous prime is 15432119999. The next prime is 15432120097. The reversal of 15432120021 is 12002123451.

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 not a de Polignac number, because 15432120021 - 2⁶ = 15432119957 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 15432120021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15432121021) 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, 2572020001 + ... + 2572020006.

It is an arithmetic number, because the mean of its divisors is an integer number (5144040008).

Almost surely, 2^15432120021 is an apocalyptic number.

It is an amenable number.

15432120021 is a deficient number, since it is larger than the sum of its proper divisors (5144040011).

15432120021 is an equidigital number, since it uses as much as digits as its factorization.

15432120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5144040010.

The product of its (nonzero) digits is 480, while the sum is 21.

Adding to 15432120021 its reverse (12002123451), we get a palindrome (27434243472).

The spelling of 15432120021 in words is "fifteen billion, four hundred thirty-two million, one hundred twenty thousand, twenty-one".