20409720 has 32 divisors (see below), whose sum is σ = 61229520. Its totient is φ = 5442560.

The previous prime is 20409713. The next prime is 20409733. The reversal of 20409720 is 2790402.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 84921 + ... + 85160.

Almost surely, 2^20409720 is an apocalyptic number.

20409720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20409720 is an abundant number, since it is smaller than the sum of its proper divisors (40819800).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20409720 is a wasteful number, since it uses less digits than its factorization.

20409720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170095 (or 170091 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 20409720 is about 4517.7118101977. The cubic root of 20409720 is about 273.2828315713.

The spelling of 20409720 in words is "twenty million, four hundred nine thousand, seven hundred twenty".