20409646 has 4 divisors (see below), whose sum is σ = 30614472. Its totient is φ = 10204822.

The previous prime is 20409643. The next prime is 20409679. The reversal of 20409646 is 64690402.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20409643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5102410 + ... + 5102413.

It is an arithmetic number, because the mean of its divisors is an integer number (7653618).

Almost surely, 2^20409646 is an apocalyptic number.

20409646 is a deficient number, since it is larger than the sum of its proper divisors (10204826).

20409646 is a wasteful number, since it uses less digits than its factorization.

20409646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10204825.

The product of its (nonzero) digits is 10368, while the sum is 31.

The square root of 20409646 is about 4517.7036202035. The cubic root of 20409646 is about 273.2825012883.

The spelling of 20409646 in words is "twenty million, four hundred nine thousand, six hundred forty-six".