61451521 has 2 divisors, whose sum is σ = 61451522. Its totient is φ = 61451520.

The previous prime is 61451519. The next prime is 61451543. The reversal of 61451521 is 12515416.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61449921 + 1600 = 7839^2 + 40^2 .

It is a cyclic number.

It is not a de Polignac number, because 61451521 - 2¹ = 61451519 is a prime.

Together with 61451519, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (61251521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30725760 + 30725761.

It is an arithmetic number, because the mean of its divisors is an integer number (30725761).

Almost surely, 2^61451521 is an apocalyptic number.

It is an amenable number.

61451521 is a deficient number, since it is larger than the sum of its proper divisors (1).

61451521 is an equidigital number, since it uses as much as digits as its factorization.

61451521 is an evil number, because the sum of its binary digits is even.

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

The square root of 61451521 is about 7839.1020531691. The cubic root of 61451521 is about 394.6185946129.

Adding to 61451521 its reverse (12515416), we get a palindrome (73966937).

The spelling of 61451521 in words is "sixty-one million, four hundred fifty-one thousand, five hundred twenty-one".