61515206251 has 4 divisors (see below), whose sum is σ = 61742199904. Its totient is φ = 61288212600.

The previous prime is 61515206219. The next prime is 61515206293. The reversal of 61515206251 is 15260251516.

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

It is a cyclic number.

It is not a de Polignac number, because 61515206251 - 2⁵ = 61515206219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61515206351) 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, 113496420 + ... + 113496961.

It is an arithmetic number, because the mean of its divisors is an integer number (15435549976).

Almost surely, 2^61515206251 is an apocalyptic number.

61515206251 is a deficient number, since it is larger than the sum of its proper divisors (226993653).

61515206251 is a wasteful number, since it uses less digits than its factorization.

61515206251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226993652.

The product of its (nonzero) digits is 18000, while the sum is 34.

Adding to 61515206251 its reverse (15260251516), we get a palindrome (76775457767).

The spelling of 61515206251 in words is "sixty-one billion, five hundred fifteen million, two hundred six thousand, two hundred fifty-one".