20725720257 has 16 divisors (see below), whose sum is σ = 30241616832. Its totient is φ = 12521411520.

The previous prime is 20725720241. The next prime is 20725720273. The reversal of 20725720257 is 75202752702.

It is an interprime number because it is at equal distance from previous prime (20725720241) and next prime (20725720273).

It is not a de Polignac number, because 20725720257 - 2⁴ = 20725720241 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20725720217) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 980158 + ... + 1001079.

It is an arithmetic number, because the mean of its divisors is an integer number (1890101052).

Almost surely, 2^20725720257 is an apocalyptic number.

It is an amenable number.

20725720257 is a deficient number, since it is larger than the sum of its proper divisors (9515896575).

20725720257 is a wasteful number, since it uses less digits than its factorization.

20725720257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1981568.

The product of its (nonzero) digits is 137200, while the sum is 39.

The spelling of 20725720257 in words is "twenty billion, seven hundred twenty-five million, seven hundred twenty thousand, two hundred fifty-seven".