20728120897 has 16 divisors (see below), whose sum is σ = 23017584960. Its totient is φ = 18506779200.

The previous prime is 20728120879. The next prime is 20728120943. The reversal of 20728120897 is 79802182702.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20728120897 - 2¹¹ = 20728118849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20728126897) 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, 694747 + ... + 723967.

It is an arithmetic number, because the mean of its divisors is an integer number (1438599060).

Almost surely, 2^20728120897 is an apocalyptic number.

It is an amenable number.

20728120897 is a deficient number, since it is larger than the sum of its proper divisors (2289464063).

20728120897 is a wasteful number, since it uses less digits than its factorization.

20728120897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30384.

The product of its (nonzero) digits is 225792, while the sum is 46.

The spelling of 20728120897 in words is "twenty billion, seven hundred twenty-eight million, one hundred twenty thousand, eight hundred ninety-seven".