61221511 has 4 divisors (see below), whose sum is σ = 65930872. Its totient is φ = 56512152.

The previous prime is 61221473. The next prime is 61221521. The reversal of 61221511 is 11512216.

61221511 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 61221511 - 2¹³ = 61213319 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61221521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2354661 + ... + 2354686.

It is an arithmetic number, because the mean of its divisors is an integer number (16482718).

Almost surely, 2^61221511 is an apocalyptic number.

61221511 is a deficient number, since it is larger than the sum of its proper divisors (4709361).

61221511 is a wasteful number, since it uses less digits than its factorization.

61221511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4709360.

The product of its digits is 120, while the sum is 19.

The square root of 61221511 is about 7824.4176141103. The cubic root of 61221511 is about 394.1256331042.

Adding to 61221511 its reverse (11512216), we get a palindrome (72733727).

The spelling of 61221511 in words is "sixty-one million, two hundred twenty-one thousand, five hundred eleven".