21099434 has 4 divisors (see below), whose sum is σ = 31649154. Its totient is φ = 10549716.

The previous prime is 21099427. The next prime is 21099451. The reversal of 21099434 is 43499012.

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., 14417209 + 6682225 = 3797^2 + 2585^2 .

It is a super-5 number, since 5×21099434⁵ (a number of 38 digits) contains 55555 as substring. Note that it is a super-d number also for d = 2.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21099434.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5274857 + ... + 5274860.

Almost surely, 2^21099434 is an apocalyptic number.

21099434 is a deficient number, since it is larger than the sum of its proper divisors (10549720).

21099434 is a wasteful number, since it uses less digits than its factorization.

21099434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10549719.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 21099434 is about 4593.4120215805. The cubic root of 21099434 is about 276.3271779885.

The spelling of 21099434 in words is "twenty-one million, ninety-nine thousand, four hundred thirty-four".