21231040442 has 4 divisors (see below), whose sum is σ = 31846560666. Its totient is φ = 10615520220.

The previous prime is 21231040417. The next prime is 21231040451. The reversal of 21231040442 is 24404013212.

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., 19931510041 + 1299530401 = 141179^2 + 36049^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5307760109 + ... + 5307760112.

Almost surely, 2^21231040442 is an apocalyptic number.

21231040442 is a deficient number, since it is larger than the sum of its proper divisors (10615520224).

21231040442 is a wasteful number, since it uses less digits than its factorization.

21231040442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10615520223.

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 21231040442 its reverse (24404013212), we get a palindrome (45635053654).

The spelling of 21231040442 in words is "twenty-one billion, two hundred thirty-one million, forty thousand, four hundred forty-two".