21051416 has 8 divisors (see below), whose sum is σ = 39471420. Its totient is φ = 10525704.

The previous prime is 21051403. The next prime is 21051421. The reversal of 21051416 is 61415012.

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

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, 1315706 + ... + 1315721.

Almost surely, 2^21051416 is an apocalyptic number.

It is an amenable number.

21051416 is a deficient number, since it is larger than the sum of its proper divisors (18420004).

21051416 is a wasteful number, since it uses less digits than its factorization.

21051416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2631433 (or 2631429 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 21051416 is about 4588.1822108543. The cubic root of 21051416 is about 276.1173973726.

Adding to 21051416 its reverse (61415012), we get a palindrome (82466428).

The spelling of 21051416 in words is "twenty-one million, fifty-one thousand, four hundred sixteen".