20907728 has 10 divisors (see below), whose sum is σ = 40508754. Its totient is φ = 10453856.

The previous prime is 20907727. The next prime is 20907743. The reversal of 20907728 is 82770902.

It can be written as a sum of positive squares in only one way, i.e., 16875664 + 4032064 = 4108^2 + 2008^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20907727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 653351 + ... + 653382.

Almost surely, 2^20907728 is an apocalyptic number.

It is an amenable number.

20907728 is a deficient number, since it is larger than the sum of its proper divisors (19601026).

20907728 is a wasteful number, since it uses less digits than its factorization.

20907728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1306741 (or 1306735 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 35.

The square root of 20907728 is about 4572.4969108792. The cubic root of 20907728 is about 275.4877426878.

The spelling of 20907728 in words is "twenty million, nine hundred seven thousand, seven hundred twenty-eight".