61221111 has 16 divisors (see below), whose sum is σ = 93401088. Its totient is φ = 34941600.

The previous prime is 61221109. The next prime is 61221137. The reversal of 61221111 is 11112216.

It is a happy number.

It is not a de Polignac number, because 61221111 - 2¹ = 61221109 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61221151) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27946 + ... + 30056.

It is an arithmetic number, because the mean of its divisors is an integer number (5837568).

Almost surely, 2^61221111 is an apocalyptic number.

61221111 is a deficient number, since it is larger than the sum of its proper divisors (32179977).

61221111 is a wasteful number, since it uses less digits than its factorization.

61221111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3502.

The product of its digits is 24, while the sum is 15.

The square root of 61221111 is about 7824.3920530607. The cubic root of 61221111 is about 394.1247747426.

Adding to 61221111 its reverse (11112216), we get a palindrome (72333327).

The spelling of 61221111 in words is "sixty-one million, two hundred twenty-one thousand, one hundred eleven".