51212139 has 8 divisors (see below), whose sum is σ = 74490432. Its totient is φ = 31037640.

The previous prime is 51212137. The next prime is 51212159. The reversal of 51212139 is 93121215.

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

It is not a de Polignac number, because 51212139 - 2¹ = 51212137 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51212131) 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, 775909 + ... + 775974.

It is an arithmetic number, because the mean of its divisors is an integer number (9311304).

Almost surely, 2^51212139 is an apocalyptic number.

51212139 is a deficient number, since it is larger than the sum of its proper divisors (23278293).

51212139 is a wasteful number, since it uses less digits than its factorization.

51212139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1551897.

The product of its digits is 540, while the sum is 24.

The square root of 51212139 is about 7156.2657161399. The cubic root of 51212139 is about 371.3564503320.

It can be divided in two parts, 5121 and 2139, that added together give a triangular number (7260 = T₁₂₀).

The spelling of 51212139 in words is "fifty-one million, two hundred twelve thousand, one hundred thirty-nine".