51451500021 has 4 divisors (see below), whose sum is σ = 68602000032. Its totient is φ = 34301000012.

The previous prime is 51451499959. The next prime is 51451500029. The reversal of 51451500021 is 12000515415.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51451500021 - 2⁹ = 51451499509 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 51451499964 and 51451500000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51451500029) 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, 8575250001 + ... + 8575250006.

It is an arithmetic number, because the mean of its divisors is an integer number (17150500008).

Almost surely, 2^51451500021 is an apocalyptic number.

It is an amenable number.

51451500021 is a deficient number, since it is larger than the sum of its proper divisors (17150500011).

51451500021 is a wasteful number, since it uses less digits than its factorization.

51451500021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17150500010.

The product of its (nonzero) digits is 1000, while the sum is 24.

The spelling of 51451500021 in words is "fifty-one billion, four hundred fifty-one million, five hundred thousand, twenty-one".