21728701570 has 8 divisors (see below), whose sum is σ = 39111662844. Its totient is φ = 8691480624.

The previous prime is 21728701523. The next prime is 21728701573. The reversal of 21728701570 is 7510782712.

It can be written as a sum of positive squares in 2 ways, for example, as 20697713689 + 1030987881 = 143867^2 + 32109^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21728701573) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1086435069 + ... + 1086435088.

Almost surely, 2^21728701570 is an apocalyptic number.

21728701570 is a deficient number, since it is larger than the sum of its proper divisors (17382961274).

21728701570 is a wasteful number, since it uses less digits than its factorization.

21728701570 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2172870164.

The product of its (nonzero) digits is 54880, while the sum is 40.

The spelling of 21728701570 in words is "twenty-one billion, seven hundred twenty-eight million, seven hundred one thousand, five hundred seventy".