661451 has 6 divisors (see below), whose sum is σ = 769500. Its totient is φ = 566916.

The previous prime is 661439. The next prime is 661459. The reversal of 661451 is 154166.

It is not a de Polignac number, because 661451 - 2¹⁴ = 645067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6701 + ... + 6798.

It is an arithmetic number, because the mean of its divisors is an integer number (128250).

2⁶⁶¹⁴⁵¹ is an apocalyptic number.

661451 is a deficient number, since it is larger than the sum of its proper divisors (108049).

661451 is a wasteful number, since it uses less digits than its factorization.

661451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13513 (or 13506 counting only the distinct ones).

The product of its digits is 720, while the sum is 23.

The square root of 661451 is about 813.2963789419. The cubic root of 661451 is about 87.1296345482.

The spelling of 661451 in words is "six hundred sixty-one thousand, four hundred fifty-one".