20998735 has 4 divisors (see below), whose sum is σ = 25198488. Its totient is φ = 16798984.

The previous prime is 20998729. The next prime is 20998739. The reversal of 20998735 is 53789902.

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 20998735 - 2³ = 20998727 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20998691 and 20998700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20998739) 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, 2099869 + ... + 2099878.

It is an arithmetic number, because the mean of its divisors is an integer number (6299622).

Almost surely, 2^20998735 is an apocalyptic number.

20998735 is a deficient number, since it is larger than the sum of its proper divisors (4199753).

20998735 is an equidigital number, since it uses as much as digits as its factorization.

20998735 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4199752.

The product of its (nonzero) digits is 136080, while the sum is 43.

The square root of 20998735 is about 4582.4376700616. The cubic root of 20998735 is about 275.8868777823.

The spelling of 20998735 in words is "twenty million, nine hundred ninety-eight thousand, seven hundred thirty-five".