21405202012 has 12 divisors (see below), whose sum is σ = 37461712680. Its totient is φ = 10701855536.

The previous prime is 21405201973. The next prime is 21405202037. The reversal of 21405202012 is 21020250412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 119062 + ... + 238717.

It is an arithmetic number, because the mean of its divisors is an integer number (3121809390).

Almost surely, 2^21405202012 is an apocalyptic number.

It is an amenable number.

21405202012 is a deficient number, since it is larger than the sum of its proper divisors (16056510668).

21405202012 is a wasteful number, since it uses less digits than its factorization.

21405202012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372740 (or 372738 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 19.

Adding to 21405202012 its reverse (21020250412), we get a palindrome (42425452424).

The spelling of 21405202012 in words is "twenty-one billion, four hundred five million, two hundred two thousand, twelve".