21187058 has 4 divisors (see below), whose sum is σ = 31780590. Its totient is φ = 10593528.

The previous prime is 21187027. The next prime is 21187063. The reversal of 21187058 is 85078112.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 12229009 + 8958049 = 3497^2 + 2993^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5296763 + ... + 5296766.

Almost surely, 2^21187058 is an apocalyptic number.

21187058 is a deficient number, since it is larger than the sum of its proper divisors (10593532).

21187058 is a wasteful number, since it uses less digits than its factorization.

21187058 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10593531.

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 21187058 is about 4602.9401473406. The cubic root of 21187058 is about 276.7091700962.

The spelling of 21187058 in words is "twenty-one million, one hundred eighty-seven thousand, fifty-eight".