21132421042 has 4 divisors (see below), whose sum is σ = 31698631566. Its totient is φ = 10566210520.

The previous prime is 21132421039. The next prime is 21132421049. The reversal of 21132421042 is 24012423112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 13961549281 + 7170871761 = 118159^2 + 84681^2 .

It is not an unprimeable number, because it can be changed into a prime (21132421049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5283105259 + ... + 5283105262.

Almost surely, 2^21132421042 is an apocalyptic number.

21132421042 is a deficient number, since it is larger than the sum of its proper divisors (10566210524).

21132421042 is a wasteful number, since it uses less digits than its factorization.

21132421042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10566210523.

The product of its (nonzero) digits is 768, while the sum is 22.

Adding to 21132421042 its reverse (24012423112), we get a palindrome (45144844154).

The spelling of 21132421042 in words is "twenty-one billion, one hundred thirty-two million, four hundred twenty-one thousand, forty-two".