51213021 has 16 divisors (see below), whose sum is σ = 69242880. Its totient is φ = 33666480.

The previous prime is 51213011. The next prime is 51213031. The reversal of 51213021 is 12031215.

It is an interprime number because it is at equal distance from previous prime (51213011) and next prime (51213031).

It is not a de Polignac number, because 51213021 - 2⁵ = 51212989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51213011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79326 + ... + 79968.

It is an arithmetic number, because the mean of its divisors is an integer number (4327680).

Almost surely, 2^51213021 is an apocalyptic number.

It is an amenable number.

51213021 is a deficient number, since it is larger than the sum of its proper divisors (18029859).

51213021 is a wasteful number, since it uses less digits than its factorization.

51213021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 976.

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 51213021 is about 7156.3273401934. The cubic root of 51213021 is about 371.3585822127.

Adding to 51213021 its reverse (12031215), we get a palindrome (63244236).

The spelling of 51213021 in words is "fifty-one million, two hundred thirteen thousand, twenty-one".