21065121652 has 12 divisors (see below), whose sum is σ = 36925509600. Its totient is φ = 10514976056.

The previous prime is 21065121631. The next prime is 21065121653. The reversal of 21065121652 is 25612156012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21065121653) 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, 4393498 + ... + 4398289.

It is an arithmetic number, because the mean of its divisors is an integer number (3077125800).

Almost surely, 2^21065121652 is an apocalyptic number.

It is an amenable number.

21065121652 is a deficient number, since it is larger than the sum of its proper divisors (15860387948).

21065121652 is a wasteful number, since it uses less digits than its factorization.

21065121652 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8792390 (or 8792388 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 31.

Adding to 21065121652 its reverse (25612156012), we get a palindrome (46677277664).

The spelling of 21065121652 in words is "twenty-one billion, sixty-five million, one hundred twenty-one thousand, six hundred fifty-two".