661162541 has 4 divisors (see below), whose sum is σ = 712021212. Its totient is φ = 610303872.

The previous prime is 661162529. The next prime is 661162543. The reversal of 661162541 is 145261166.

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 288286441 + 372876100 = 16979^2 + 19310^2 .

It is a cyclic number.

It is not a de Polignac number, because 661162541 - 2¹⁸ = 660900397 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 661162498 and 661162507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661162543) 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, 25429316 + ... + 25429341.

It is an arithmetic number, because the mean of its divisors is an integer number (178005303).

Almost surely, 2^661162541 is an apocalyptic number.

It is an amenable number.

661162541 is a deficient number, since it is larger than the sum of its proper divisors (50858671).

661162541 is a wasteful number, since it uses less digits than its factorization.

661162541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50858670.

The product of its digits is 8640, while the sum is 32.

The square root of 661162541 is about 25713.0811261506. The cubic root of 661162541 is about 871.1696695243.

The spelling of 661162541 in words is "six hundred sixty-one million, one hundred sixty-two thousand, five hundred forty-one".