21137099 has 4 divisors (see below), whose sum is σ = 21652680. Its totient is φ = 20621520.

The previous prime is 21137087. The next prime is 21137107. The reversal of 21137099 is 99073112.

It is a happy number.

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 21137099 - 2¹² = 21133003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21137999) 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, 257729 + ... + 257810.

It is an arithmetic number, because the mean of its divisors is an integer number (5413170).

Almost surely, 2^21137099 is an apocalyptic number.

21137099 is a deficient number, since it is larger than the sum of its proper divisors (515581).

21137099 is an equidigital number, since it uses as much as digits as its factorization.

21137099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 515580.

The product of its (nonzero) digits is 3402, while the sum is 32.

The square root of 21137099 is about 4597.5100869927. The cubic root of 21137099 is about 276.4915058752.

The spelling of 21137099 in words is "twenty-one million, one hundred thirty-seven thousand, ninety-nine".