21137051 has 4 divisors (see below), whose sum is σ = 22762992. Its totient is φ = 19511112.

The previous prime is 21137041. The next prime is 21137057. The reversal of 21137051 is 15073112.

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

It is a cyclic number.

It is not a de Polignac number, because 21137051 - 2¹⁴ = 21120667 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21137057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 812951 + ... + 812976.

It is an arithmetic number, because the mean of its divisors is an integer number (5690748).

Almost surely, 2^21137051 is an apocalyptic number.

21137051 is a deficient number, since it is larger than the sum of its proper divisors (1625941).

21137051 is a wasteful number, since it uses less digits than its factorization.

21137051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1625940.

The product of its (nonzero) digits is 210, while the sum is 20.

The square root of 21137051 is about 4597.5048667728. The cubic root of 21137051 is about 276.4912965813.

The spelling of 21137051 in words is "twenty-one million, one hundred thirty-seven thousand, fifty-one".