21402025252 has 6 divisors (see below), whose sum is σ = 37453544198. Its totient is φ = 10701012624.

The previous prime is 21402025243. The next prime is 21402025289. The reversal of 21402025252 is 25252020412.

It can be written as a sum of positive squares in only one way, i.e., 17128003876 + 4274021376 = 130874^2 + 65376^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2675253153 + ... + 2675253160.

Almost surely, 2^21402025252 is an apocalyptic number.

It is an amenable number.

21402025252 is a deficient number, since it is larger than the sum of its proper divisors (16051518946).

21402025252 is a wasteful number, since it uses less digits than its factorization.

21402025252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5350506317 (or 5350506315 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 25.

Adding to 21402025252 its reverse (25252020412), we get a palindrome (46654045664).

The spelling of 21402025252 in words is "twenty-one billion, four hundred two million, twenty-five thousand, two hundred fifty-two".