20909349 has 6 divisors (see below), whose sum is σ = 30202406. Its totient is φ = 13939560.

The previous prime is 20909347. The next prime is 20909363. The reversal of 20909349 is 94390902.

20909349 = T₁₂₃₁ + T₁₂₃₂ + ... + T₁₂₅₇.

It can be written as a sum of positive squares in only one way, i.e., 20412324 + 497025 = 4518^2 + 705^2 .

It is not a de Polignac number, because 20909349 - 2¹ = 20909347 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20909347) by changing a digit.

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 in 5 ways as a sum of consecutive naturals, for example, 1161622 + ... + 1161639.

Almost surely, 2^20909349 is an apocalyptic number.

It is an amenable number.

20909349 is a deficient number, since it is larger than the sum of its proper divisors (9293057).

20909349 is a wasteful number, since it uses less digits than its factorization.

20909349 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2323267 (or 2323264 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 36.

The square root of 20909349 is about 4572.6741628942. The cubic root of 20909349 is about 275.4948621302.

The spelling of 20909349 in words is "twenty million, nine hundred nine thousand, three hundred forty-nine".