20649407 has 4 divisors (see below), whose sum is σ = 21864096. Its totient is φ = 19434720.

The previous prime is 20649397. The next prime is 20649413. The reversal of 20649407 is 70494602.

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 20649407 - 2¹² = 20645311 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 (20649907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 607319 + ... + 607352.

It is an arithmetic number, because the mean of its divisors is an integer number (5466024).

Almost surely, 2^20649407 is an apocalyptic number.

20649407 is a deficient number, since it is larger than the sum of its proper divisors (1214689).

20649407 is a wasteful number, since it uses less digits than its factorization.

20649407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1214688.

The product of its (nonzero) digits is 12096, while the sum is 32.

The square root of 20649407 is about 4544.1618589130. The cubic root of 20649407 is about 274.3484608768.

The spelling of 20649407 in words is "twenty million, six hundred forty-nine thousand, four hundred seven".