21040699 has 4 divisors (see below), whose sum is σ = 21955536. Its totient is φ = 20125864.

The previous prime is 21040697. The next prime is 21040703. The reversal of 21040699 is 99604012.

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 21040699 - 2¹ = 21040697 is a prime.

It is a super-2 number, since 2×21040699² = 885422028817202, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21040699.

It is not an unprimeable number, because it can be changed into a prime (21040697) 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, 457384 + ... + 457429.

It is an arithmetic number, because the mean of its divisors is an integer number (5488884).

Almost surely, 2^21040699 is an apocalyptic number.

21040699 is a deficient number, since it is larger than the sum of its proper divisors (914837).

21040699 is an equidigital number, since it uses as much as digits as its factorization.

21040699 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 914836.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 21040699 is about 4587.0141704599. The cubic root of 21040699 is about 276.0705335030.

The spelling of 21040699 in words is "twenty-one million, forty thousand, six hundred ninety-nine".