651081 has 4 divisors (see below), whose sum is σ = 868112. Its totient is φ = 434052.

The previous prime is 651071. The next prime is 651097. The reversal of 651081 is 180156.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 651081 - 2⁶ = 651017 is a prime.

It is a super-2 number, since 2×651081² = 847812937122, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (651071) 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, 108511 + ... + 108516.

It is an arithmetic number, because the mean of its divisors is an integer number (217028).

2⁶⁵¹⁰⁸¹ is an apocalyptic number.

It is an amenable number.

651081 is a deficient number, since it is larger than the sum of its proper divisors (217031).

651081 is a wasteful number, since it uses less digits than its factorization.

651081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217030.

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 651081 is about 806.8959040669. The cubic root of 651081 is about 86.6719046801.

The spelling of 651081 in words is "six hundred fifty-one thousand, eighty-one".