51099421 has 4 divisors (see below), whose sum is σ = 52861500. Its totient is φ = 49337344.

The previous prime is 51099409. The next prime is 51099427. The reversal of 51099421 is 12499015.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12499015 = 5 ⋅2499803.

It can be written as a sum of positive squares in 2 ways, for example, as 16112196 + 34987225 = 4014^2 + 5915^2 .

It is a cyclic number.

It is not a de Polignac number, because 51099421 - 2⁹ = 51098909 is a prime.

It is a super-2 number, since 2×51099421² = 5222301653070482, 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 (51099427) 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, 880996 + ... + 881053.

It is an arithmetic number, because the mean of its divisors is an integer number (13215375).

Almost surely, 2^51099421 is an apocalyptic number.

It is an amenable number.

51099421 is a deficient number, since it is larger than the sum of its proper divisors (1762079).

51099421 is a wasteful number, since it uses less digits than its factorization.

51099421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1762078.

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 51099421 is about 7148.3859017263. The cubic root of 51099421 is about 371.0837981507.

The spelling of 51099421 in words is "fifty-one million, ninety-nine thousand, four hundred twenty-one".