61551521 has 4 divisors (see below), whose sum is σ = 62161044. Its totient is φ = 60942000.

The previous prime is 61551517. The next prime is 61551559. The reversal of 61551521 is 12515516.

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

It can be written as a sum of positive squares in 2 ways, for example, as 34093921 + 27457600 = 5839^2 + 5240^2 .

It is a cyclic number.

It is not a de Polignac number, because 61551521 - 2² = 61551517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61551121) 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, 304610 + ... + 304811.

It is an arithmetic number, because the mean of its divisors is an integer number (15540261).

Almost surely, 2^61551521 is an apocalyptic number.

It is an amenable number.

61551521 is a deficient number, since it is larger than the sum of its proper divisors (609523).

61551521 is a wasteful number, since it uses less digits than its factorization.

61551521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 609522.

The product of its digits is 1500, while the sum is 26.

The square root of 61551521 is about 7845.4777419861. The cubic root of 61551521 is about 394.8325327587.

The spelling of 61551521 in words is "sixty-one million, five hundred fifty-one thousand, five hundred twenty-one".