51554750021 has 4 divisors (see below), whose sum is σ = 51568774572. Its totient is φ = 51540725472.

The previous prime is 51554750003. The next prime is 51554750041. The reversal of 51554750021 is 12005745515.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 42595180996 + 8959569025 = 206386^2 + 94655^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51554750021 is a prime.

It is a super-3 number, since 3×51554750021³ (a number of 33 digits) contains 333 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 (51554750041) 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, 7006760 + ... + 7014113.

It is an arithmetic number, because the mean of its divisors is an integer number (12892193643).

Almost surely, 2^51554750021 is an apocalyptic number.

It is an amenable number.

51554750021 is a deficient number, since it is larger than the sum of its proper divisors (14024551).

51554750021 is a wasteful number, since it uses less digits than its factorization.

51554750021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14024550.

The product of its (nonzero) digits is 35000, while the sum is 35.

The spelling of 51554750021 in words is "fifty-one billion, five hundred fifty-four million, seven hundred fifty thousand, twenty-one".