21100402042 has 8 divisors (see below), whose sum is σ = 31652370036. Its totient is φ = 10549612032.

The previous prime is 21100402007. The next prime is 21100402049. The reversal of 21100402042 is 24020400112.

It can be written as a sum of positive squares in 2 ways, for example, as 18724911921 + 2375490121 = 136839^2 + 48739^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21100402049) 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, 248263 + ... + 322234.

Almost surely, 2^21100402042 is an apocalyptic number.

21100402042 is a deficient number, since it is larger than the sum of its proper divisors (10551967994).

21100402042 is a wasteful number, since it uses less digits than its factorization.

21100402042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 588992.

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 21100402042 its reverse (24020400112), we get a palindrome (45120802154).

The spelling of 21100402042 in words is "twenty-one billion, one hundred million, four hundred two thousand, forty-two".