861951 has 8 divisors (see below), whose sum is σ = 1216944. Its totient is φ = 540800.

The previous prime is 861947. The next prime is 861977. The reversal of 861951 is 159168.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 861951 - 2² = 861947 is a prime.

861951 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 861951.

It is not an unprimeable number, because it can be changed into a prime (861901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8400 + ... + 8501.

It is an arithmetic number, because the mean of its divisors is an integer number (152118).

2⁸⁶¹⁹⁵¹ is an apocalyptic number.

861951 is a deficient number, since it is larger than the sum of its proper divisors (354993).

861951 is a wasteful number, since it uses less digits than its factorization.

861951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16921.

The product of its digits is 2160, while the sum is 30.

The square root of 861951 is about 928.4131623367. The cubic root of 861951 is about 95.1687122073.

It can be divided in two parts, 8619 and 51, that multiplied together give a square (439569 = 663²).

The spelling of 861951 in words is "eight hundred sixty-one thousand, nine hundred fifty-one".