65001557021 has 4 divisors (see below), whose sum is σ = 65002921500. Its totient is φ = 65000192544.

The previous prime is 65001556999. The next prime is 65001557053. The reversal of 65001557021 is 12075510056.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 46047151396 + 18954405625 = 214586^2 + 137675^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-65001557021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65001557081) 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, 608096 + ... + 706953.

It is an arithmetic number, because the mean of its divisors is an integer number (16250730375).

Almost surely, 2^65001557021 is an apocalyptic number.

It is an amenable number.

65001557021 is a deficient number, since it is larger than the sum of its proper divisors (1364479).

65001557021 is a wasteful number, since it uses less digits than its factorization.

65001557021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1364478.

The product of its (nonzero) digits is 10500, while the sum is 32.

The spelling of 65001557021 in words is "sixty-five billion, one million, five hundred fifty-seven thousand, twenty-one".