651861 has 16 divisors (see below), whose sum is σ = 1104000. Its totient is φ = 372384.

The previous prime is 651857. The next prime is 651863. The reversal of 651861 is 168156.

651861 is a `hidden beast` number, since 651 + 8 + 6 + 1 = 666.

It is not a de Polignac number, because 651861 - 2² = 651857 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (651863) 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 15 ways as a sum of consecutive naturals, for example, 1536 + ... + 1913.

It is an arithmetic number, because the mean of its divisors is an integer number (69000).

2⁶⁵¹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

651861 is a deficient number, since it is larger than the sum of its proper divisors (452139).

651861 is a wasteful number, since it uses less digits than its factorization.

651861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3465 (or 3459 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 651861 is about 807.3790931155. The cubic root of 651861 is about 86.7065020686.

The spelling of 651861 in words is "six hundred fifty-one thousand, eight hundred sixty-one".