51155434021 has 12 divisors (see below), whose sum is σ = 52877869632. Its totient is φ = 49487439000.

The previous prime is 51155434013. The next prime is 51155434037. The reversal of 51155434021 is 12043455115.

It is not a de Polignac number, because 51155434021 - 2³ = 51155434013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51155434721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3231636 + ... + 3247426.

It is an arithmetic number, because the mean of its divisors is an integer number (4406489136).

Almost surely, 2^51155434021 is an apocalyptic number.

It is an amenable number.

51155434021 is a deficient number, since it is larger than the sum of its proper divisors (1722435611).

51155434021 is a wasteful number, since it uses less digits than its factorization.

51155434021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19224 (or 19193 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 31.

Adding to 51155434021 its reverse (12043455115), we get a palindrome (63198889136).

The spelling of 51155434021 in words is "fifty-one billion, one hundred fifty-five million, four hundred thirty-four thousand, twenty-one".