51215641 has 4 divisors (see below), whose sum is σ = 53442432. Its totient is φ = 48988852.

The previous prime is 51215609. The next prime is 51215651. The reversal of 51215641 is 14651215.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 14651215 = 5 ⋅2930243.

It is a cyclic number.

It is not a de Polignac number, because 51215641 - 2⁵ = 51215609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51215651) 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, 1113361 + ... + 1113406.

It is an arithmetic number, because the mean of its divisors is an integer number (13360608).

Almost surely, 2^51215641 is an apocalyptic number.

It is an amenable number.

51215641 is a deficient number, since it is larger than the sum of its proper divisors (2226791).

51215641 is a wasteful number, since it uses less digits than its factorization.

51215641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2226790.

The product of its digits is 1200, while the sum is 25.

The square root of 51215641 is about 7156.5103926425. The cubic root of 51215641 is about 371.3649148658.

Adding to 51215641 its reverse (14651215), we get a palindrome (65866856).

The spelling of 51215641 in words is "fifty-one million, two hundred fifteen thousand, six hundred forty-one".