61491481 has 2 divisors, whose sum is σ = 61491482. Its totient is φ = 61491480.

The previous prime is 61491457. The next prime is 61491497. The reversal of 61491481 is 18419416.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50993881 + 10497600 = 7141^2 + 3240^2 .

It is a cyclic number.

It is not a de Polignac number, because 61491481 - 2⁹ = 61490969 is a prime.

It is a super-2 number, since 2×61491481² = 7562404471146722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (61491401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30745740 + 30745741.

It is an arithmetic number, because the mean of its divisors is an integer number (30745741).

Almost surely, 2^61491481 is an apocalyptic number.

It is an amenable number.

61491481 is a deficient number, since it is larger than the sum of its proper divisors (1).

61491481 is an equidigital number, since it uses as much as digits as its factorization.

61491481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 34.

The square root of 61491481 is about 7841.6504002665. The cubic root of 61491481 is about 394.7041121179.

The spelling of 61491481 in words is "sixty-one million, four hundred ninety-one thousand, four hundred eighty-one".