51810381 has 32 divisors (see below), whose sum is σ = 88058880. Its totient is φ = 29492208.

The previous prime is 51810379. The next prime is 51810383. The reversal of 51810381 is 18301815.

It is an interprime number because it is at equal distance from previous prime (51810379) and next prime (51810383).

It is not a de Polignac number, because 51810381 - 2¹ = 51810379 is a prime.

It is a super-2 number, since 2×51810381² = 5368631158730322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51810383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 87970 + ... + 88556.

It is an arithmetic number, because the mean of its divisors is an integer number (2751840).

Almost surely, 2^51810381 is an apocalyptic number.

It is an amenable number.

51810381 is a deficient number, since it is larger than the sum of its proper divisors (36248499).

51810381 is a wasteful number, since it uses less digits than its factorization.

51810381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1070 (or 1064 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 27.

The square root of 51810381 is about 7197.9428311150. The cubic root of 51810381 is about 372.7968739760.

The spelling of 51810381 in words is "fifty-one million, eight hundred ten thousand, three hundred eighty-one".