61491111 has 24 divisors (see below), whose sum is σ = 91629552. Its totient is φ = 36643200.

The previous prime is 61491109. The next prime is 61491119. The reversal of 61491111 is 11119416.

It is not a de Polignac number, because 61491111 - 2¹ = 61491109 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61491119) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20755 + ... + 23531.

It is an arithmetic number, because the mean of its divisors is an integer number (3817898).

Almost surely, 2^61491111 is an apocalyptic number.

61491111 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

61491111 is a deficient number, since it is larger than the sum of its proper divisors (30138441).

61491111 is a wasteful number, since it uses less digits than its factorization.

61491111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2863 (or 2852 counting only the distinct ones).

The product of its digits is 216, while the sum is 24.

The square root of 61491111 is about 7841.6268082586. The cubic root of 61491111 is about 394.7033204591.

It can be divided in two parts, 6149 and 1111, that added together give a triangular number (7260 = T₁₂₀).

The spelling of 61491111 in words is "sixty-one million, four hundred ninety-one thousand, one hundred eleven".