28243765447921 has 16 divisors (see below), whose sum is σ = 29297318658048. Its totient is φ = 27210305581200.

The previous prime is 28243765447913. The next prime is 28243765448021. The reversal of 28243765447921 is 12974456734282.

It is a cyclic number.

It is not a de Polignac number, because 28243765447921 - 2³ = 28243765447913 is a prime.

It is a super-2 number, since 2×28243765447921² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28243765447321) 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, 4601025 + ... + 8812318.

It is an arithmetic number, because the mean of its divisors is an integer number (1831082416128).

Almost surely, 2^{28243765447921} is an apocalyptic number.

It is an amenable number.

28243765447921 is a deficient number, since it is larger than the sum of its proper divisors (1053553210127).

28243765447921 is a wasteful number, since it uses less digits than its factorization.

28243765447921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13414092.

The product of its digits is 162570240, while the sum is 64.

The spelling of 28243765447921 in words is "twenty-eight trillion, two hundred forty-three billion, seven hundred sixty-five million, four hundred forty-seven thousand, nine hundred twenty-one".