28573132721 has 32 divisors (see below), whose sum is σ = 35091060480. Its totient is φ = 22707910656.

The previous prime is 28573132717. The next prime is 28573132787. The reversal of 28573132721 is 12723137582.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 28573132721 - 2² = 28573132717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28573132711) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10744490 + ... + 10747148.

It is an arithmetic number, because the mean of its divisors is an integer number (1096595640).

Almost surely, 2^28573132721 is an apocalyptic number.

It is an amenable number.

28573132721 is a deficient number, since it is larger than the sum of its proper divisors (6517927759).

28573132721 is a wasteful number, since it uses less digits than its factorization.

28573132721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3993.

The product of its digits is 141120, while the sum is 41.

The spelling of 28573132721 in words is "twenty-eight billion, five hundred seventy-three million, one hundred thirty-two thousand, seven hundred twenty-one".