21123003652 has 6 divisors (see below), whose sum is σ = 36965256398. Its totient is φ = 10561501824.

The previous prime is 21123003631. The next prime is 21123003679. The reversal of 21123003652 is 25630032112.

It can be written as a sum of positive squares in only one way, i.e., 12860920836 + 8262082816 = 113406^2 + 90896^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640375453 + ... + 2640375460.

Almost surely, 2^21123003652 is an apocalyptic number.

It is an amenable number.

21123003652 is a deficient number, since it is larger than the sum of its proper divisors (15842252746).

21123003652 is a wasteful number, since it uses less digits than its factorization.

21123003652 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5280750917 (or 5280750915 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 25.

Adding to 21123003652 its reverse (25630032112), we get a palindrome (46753035764).

The spelling of 21123003652 in words is "twenty-one billion, one hundred twenty-three million, three thousand, six hundred fifty-two".