21025648918 has 4 divisors (see below), whose sum is σ = 31538473380. Its totient is φ = 10512824458.

The previous prime is 21025648907. The next prime is 21025648937. The reversal of 21025648918 is 81984652012.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5256412228 + ... + 5256412231.

It is an arithmetic number, because the mean of its divisors is an integer number (7884618345).

Almost surely, 2^21025648918 is an apocalyptic number.

21025648918 is a deficient number, since it is larger than the sum of its proper divisors (10512824462).

21025648918 is a wasteful number, since it uses less digits than its factorization.

21025648918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10512824461.

The product of its (nonzero) digits is 276480, while the sum is 46.

The spelling of 21025648918 in words is "twenty-one billion, twenty-five million, six hundred forty-eight thousand, nine hundred eighteen".