21110251402 has 4 divisors (see below), whose sum is σ = 31665377106. Its totient is φ = 10555125700.

The previous prime is 21110251373. The next prime is 21110251403. The reversal of 21110251402 is 20415201112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 18493008121 + 2617243281 = 135989^2 + 51159^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21110251402.

It is not an unprimeable number, because it can be changed into a prime (21110251403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5277562849 + ... + 5277562852.

Almost surely, 2^21110251402 is an apocalyptic number.

21110251402 is a deficient number, since it is larger than the sum of its proper divisors (10555125704).

21110251402 is a wasteful number, since it uses less digits than its factorization.

21110251402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10555125703.

The product of its (nonzero) digits is 160, while the sum is 19.

Adding to 21110251402 its reverse (20415201112), we get a palindrome (41525452514).

The spelling of 21110251402 in words is "twenty-one billion, one hundred ten million, two hundred fifty-one thousand, four hundred two".