921671657 has 4 divisors (see below), whose sum is σ = 924312900. Its totient is φ = 919030416.

The previous prime is 921671651. The next prime is 921671671. The reversal of 921671657 is 756176129.

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 488365801 + 433305856 = 22099^2 + 20816^2 .

It is a cyclic number.

It is not a de Polignac number, because 921671657 - 2¹⁶ = 921606121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (921671651) 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, 1320098 + ... + 1320795.

It is an arithmetic number, because the mean of its divisors is an integer number (231078225).

Almost surely, 2^921671657 is an apocalyptic number.

It is an amenable number.

921671657 is a deficient number, since it is larger than the sum of its proper divisors (2641243).

921671657 is a wasteful number, since it uses less digits than its factorization.

921671657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2641242.

The product of its digits is 158760, while the sum is 44.

The square root of 921671657 is about 30359.0457195216. The cubic root of 921671657 is about 973.1775404175.

The spelling of 921671657 in words is "nine hundred twenty-one million, six hundred seventy-one thousand, six hundred fifty-seven".