20720642 has 8 divisors (see below), whose sum is σ = 31110156. Its totient is φ = 10350592.

The previous prime is 20720633. The next prime is 20720653. The reversal of 20720642 is 24602702.

It can be written as a sum of positive squares in 2 ways, for example, as 19616041 + 1104601 = 4429^2 + 1051^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1823 + ... + 6690.

Almost surely, 2^20720642 is an apocalyptic number.

20720642 is a deficient number, since it is larger than the sum of its proper divisors (10389514).

20720642 is a wasteful number, since it uses less digits than its factorization.

20720642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9732.

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 20720642 is about 4551.9931898016. The cubic root of 20720642 is about 274.6635753755.

The spelling of 20720642 in words is "twenty million, seven hundred twenty thousand, six hundred forty-two".