51621171517 has 4 divisors (see below), whose sum is σ = 54657711036. Its totient is φ = 48584632000.

The previous prime is 51621171499. The next prime is 51621171533. The reversal of 51621171517 is 71517112615.

It is a happy number.

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 27886996036 + 23734175481 = 166994^2 + 154059^2 .

It is a cyclic number.

It is not a de Polignac number, because 51621171517 - 2¹¹ = 51621169469 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51621171587) 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, 1518269734 + ... + 1518269767.

It is an arithmetic number, because the mean of its divisors is an integer number (13664427759).

Almost surely, 2^51621171517 is an apocalyptic number.

It is an amenable number.

51621171517 is a deficient number, since it is larger than the sum of its proper divisors (3036539519).

51621171517 is a wasteful number, since it uses less digits than its factorization.

51621171517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3036539518.

The product of its digits is 14700, while the sum is 37.

The spelling of 51621171517 in words is "fifty-one billion, six hundred twenty-one million, one hundred seventy-one thousand, five hundred seventeen".