61451320321 has 4 divisors (see below), whose sum is σ = 61452320944. Its totient is φ = 61450319700.

The previous prime is 61451320303. The next prime is 61451320349. The reversal of 61451320321 is 12302315416.

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 61451320321 - 2⁵ = 61451320289 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 61451320321.

It is not an unprimeable number, because it can be changed into a prime (61451320391) 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, 401715 + ... + 533176.

It is an arithmetic number, because the mean of its divisors is an integer number (15363080236).

Almost surely, 2^61451320321 is an apocalyptic number.

It is an amenable number.

61451320321 is a deficient number, since it is larger than the sum of its proper divisors (1000623).

61451320321 is an equidigital number, since it uses as much as digits as its factorization.

61451320321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1000622.

The product of its (nonzero) digits is 4320, while the sum is 28.

Adding to 61451320321 its reverse (12302315416), we get a palindrome (73753635737).

The spelling of 61451320321 in words is "sixty-one billion, four hundred fifty-one million, three hundred twenty thousand, three hundred twenty-one".