21251401016 has 8 divisors (see below), whose sum is σ = 39846376920. Its totient is φ = 10625700504.

The previous prime is 21251401001. The next prime is 21251401037. The reversal of 21251401016 is 61010415212.

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 21251400982 and 21251401000.

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, 1328212556 + ... + 1328212571.

It is an arithmetic number, because the mean of its divisors is an integer number (4980797115).

Almost surely, 2^21251401016 is an apocalyptic number.

It is an amenable number.

21251401016 is a deficient number, since it is larger than the sum of its proper divisors (18594975904).

21251401016 is a wasteful number, since it uses less digits than its factorization.

21251401016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2656425133 (or 2656425129 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 23.

Adding to 21251401016 its reverse (61010415212), we get a palindrome (82261816228).

The spelling of 21251401016 in words is "twenty-one billion, two hundred fifty-one million, four hundred one thousand, sixteen".