20477721 has 16 divisors (see below), whose sum is σ = 30064320. Its totient is φ = 12294720.

The previous prime is 20477711. The next prime is 20477731. The reversal of 20477721 is 12777402.

It is an interprime number because it is at equal distance from previous prime (20477711) and next prime (20477731).

It is not a de Polignac number, because 20477721 - 2⁷ = 20477593 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20477711) 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 15 ways as a sum of consecutive naturals, for example, 751 + ... + 6443.

It is an arithmetic number, because the mean of its divisors is an integer number (1879020).

Almost surely, 2^20477721 is an apocalyptic number.

It is an amenable number.

20477721 is a deficient number, since it is larger than the sum of its proper divisors (9586599).

20477721 is a wasteful number, since it uses less digits than its factorization.

20477721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5816.

The product of its (nonzero) digits is 5488, while the sum is 30.

The square root of 20477721 is about 4525.2315962832. The cubic root of 20477721 is about 273.5860025627.

The spelling of 20477721 in words is "twenty million, four hundred seventy-seven thousand, seven hundred twenty-one".