20731477 has 4 divisors (see below), whose sum is σ = 22326220. Its totient is φ = 19136736.

The previous prime is 20731457. The next prime is 20731499. The reversal of 20731477 is 77413702.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11737476 + 8994001 = 3426^2 + 2999^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20731477 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 (20731457) 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 3 ways as a sum of consecutive naturals, for example, 797352 + ... + 797377.

It is an arithmetic number, because the mean of its divisors is an integer number (5581555).

Almost surely, 2^20731477 is an apocalyptic number.

It is an amenable number.

20731477 is a deficient number, since it is larger than the sum of its proper divisors (1594743).

20731477 is a wasteful number, since it uses less digits than its factorization.

20731477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1594742.

The product of its (nonzero) digits is 8232, while the sum is 31.

The square root of 20731477 is about 4553.1831722433. The cubic root of 20731477 is about 274.7114416734.

It can be divided in two parts, 207 and 31477, that added together give a square (31684 = 178²).

The spelling of 20731477 in words is "twenty million, seven hundred thirty-one thousand, four hundred seventy-seven".