51567981 has 4 divisors (see below), whose sum is σ = 68757312. Its totient is φ = 34378652.

The previous prime is 51567979. The next prime is 51568007. The reversal of 51567981 is 18976515.

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 a cyclic number.

It is not a de Polignac number, because 51567981 - 2¹ = 51567979 is a prime.

It is a super-2 number, since 2×51567981² = 5318513328832722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51567281) 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, 8594661 + ... + 8594666.

It is an arithmetic number, because the mean of its divisors is an integer number (17189328).

Almost surely, 2^51567981 is an apocalyptic number.

It is an amenable number.

51567981 is a deficient number, since it is larger than the sum of its proper divisors (17189331).

51567981 is a wasteful number, since it uses less digits than its factorization.

51567981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17189330.

The product of its digits is 75600, while the sum is 42.

The square root of 51567981 is about 7181.0849458839. The cubic root of 51567981 is about 372.2145758815.

The spelling of 51567981 in words is "fifty-one million, five hundred sixty-seven thousand, nine hundred eighty-one".