2921925661 has 4 divisors (see below), whose sum is σ = 2928866524. Its totient is φ = 2914984800.

The previous prime is 2921925647. The next prime is 2921925683. The reversal of 2921925661 is 1665291292.

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 490844025 + 2431081636 = 22155^2 + 49306^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2921925661 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 (2921925641) 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, 3469800 + ... + 3470641.

It is an arithmetic number, because the mean of its divisors is an integer number (732216631).

Almost surely, 2^2921925661 is an apocalyptic number.

It is an amenable number.

2921925661 is a deficient number, since it is larger than the sum of its proper divisors (6940863).

2921925661 is an equidigital number, since it uses as much as digits as its factorization.

2921925661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6940862.

The product of its digits is 116640, while the sum is 43.

The square root of 2921925661 is about 54054.8393855721. The cubic root of 2921925661 is about 1429.6280286690.

The spelling of 2921925661 in words is "two billion, nine hundred twenty-one million, nine hundred twenty-five thousand, six hundred sixty-one".