21080051 has 8 divisors (see below), whose sum is σ = 22699440. Its totient is φ = 19502848.

The previous prime is 21080041. The next prime is 21080057. The reversal of 21080051 is 15008012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21080051 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21080057) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9506 + ... + 11511.

It is an arithmetic number, because the mean of its divisors is an integer number (2837430).

Almost surely, 2^21080051 is an apocalyptic number.

21080051 is a deficient number, since it is larger than the sum of its proper divisors (1619389).

21080051 is a wasteful number, since it uses less digits than its factorization.

21080051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21093.

The product of its (nonzero) digits is 80, while the sum is 17.

The square root of 21080051 is about 4591.3016672835. The cubic root of 21080051 is about 276.2425360554.

Adding to 21080051 its reverse (15008012), we get a palindrome (36088063).

The spelling of 21080051 in words is "twenty-one million, eighty thousand, fifty-one".