21131242444 has 24 divisors (see below), whose sum is σ = 39843319040. Its totient is φ = 9748214784.

The previous prime is 21131242427. The next prime is 21131242463. The reversal of 21131242444 is 44424213112.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13717 + ... + 206035.

Almost surely, 2^21131242444 is an apocalyptic number.

It is an amenable number.

21131242444 is a deficient number, since it is larger than the sum of its proper divisors (18712076596).

21131242444 is a wasteful number, since it uses less digits than its factorization.

21131242444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194449 (or 194447 counting only the distinct ones).

The product of its digits is 6144, while the sum is 28.

Adding to 21131242444 its reverse (44424213112), we get a palindrome (65555455556).

The spelling of 21131242444 in words is "twenty-one billion, one hundred thirty-one million, two hundred forty-two thousand, four hundred forty-four".