951811981 has 8 divisors (see below), whose sum is σ = 962033400. Its totient is φ = 941606400.

The previous prime is 951811957. The next prime is 951812023. The reversal of 951811981 is 189118159.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 369024100 + 582787881 = 19210^2 + 24141^2 .

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 951811981 - 2¹⁷ = 951680909 is a prime.

It is a super-2 number, since 2×951811981² = 1811892094350288722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (951811901) 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, 147225 + ... + 153553.

It is an arithmetic number, because the mean of its divisors is an integer number (120254175).

Almost surely, 2^951811981 is an apocalyptic number.

It is an amenable number.

951811981 is a deficient number, since it is larger than the sum of its proper divisors (10221419).

951811981 is a wasteful number, since it uses less digits than its factorization.

951811981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7919.

The product of its digits is 25920, while the sum is 43.

The square root of 951811981 is about 30851.4502252325. The cubic root of 951811981 is about 983.6721802899.

The spelling of 951811981 in words is "nine hundred fifty-one million, eight hundred eleven thousand, nine hundred eighty-one".