921129533257 has 4 divisors (see below), whose sum is σ = 921135414420. Its totient is φ = 921123652096.

The previous prime is 921129533249. The next prime is 921129533273. The reversal of 921129533257 is 752335921129.

It is a happy number.

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 653614039296 + 267515493961 = 808464^2 + 517219^2 .

It is a cyclic number.

It is not a de Polignac number, because 921129533257 - 2³ = 921129533249 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 921129533257.

It is not an unprimeable number, because it can be changed into a prime (921129533557) 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, 2699032 + ... + 3021097.

It is an arithmetic number, because the mean of its divisors is an integer number (230283853605).

Almost surely, 2^921129533257 is an apocalyptic number.

It is an amenable number.

921129533257 is a deficient number, since it is larger than the sum of its proper divisors (5881163).

921129533257 is a wasteful number, since it uses less digits than its factorization.

921129533257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5881162.

The product of its digits is 1020600, while the sum is 49.

The spelling of 921129533257 in words is "nine hundred twenty-one billion, one hundred twenty-nine million, five hundred thirty-three thousand, two hundred fifty-seven".