51559981 has 8 divisors (see below), whose sum is σ = 57767904. Its totient is φ = 45605520.

The previous prime is 51559961. The next prime is 51560009. The reversal of 51559981 is 18995515.

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 51559981 - 2¹³ = 51551789 is a prime.

It is a super-2 number, since 2×51559981² = 5316863281440722, 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 (51559961) 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, 62935 + ... + 63748.

It is an arithmetic number, because the mean of its divisors is an integer number (7220988).

Almost surely, 2^51559981 is an apocalyptic number.

It is an amenable number.

51559981 is a deficient number, since it is larger than the sum of its proper divisors (6207923).

51559981 is a wasteful number, since it uses less digits than its factorization.

51559981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126731.

The product of its digits is 81000, while the sum is 43.

The square root of 51559981 is about 7180.5279053841. The cubic root of 51559981 is about 372.1953270469.

The spelling of 51559981 in words is "fifty-one million, five hundred fifty-nine thousand, nine hundred eighty-one".