21004042052 has 24 divisors (see below), whose sum is σ = 42441162624. Its totient is φ = 8908929792.

The previous prime is 21004042027. The next prime is 21004042061. The reversal of 21004042052 is 25024040012.

It is a happy number.

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, 3864008 + ... + 3869439.

It is an arithmetic number, because the mean of its divisors is an integer number (1768381776).

Almost surely, 2^21004042052 is an apocalyptic number.

It is an amenable number.

21004042052 is an abundant number, since it is smaller than the sum of its proper divisors (21437120572).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21004042052 is a wasteful number, since it uses less digits than its factorization.

21004042052 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7733555 (or 7733553 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 20.

Adding to 21004042052 its reverse (25024040012), we get a palindrome (46028082064).

The spelling of 21004042052 in words is "twenty-one billion, four million, forty-two thousand, fifty-two".