61439681 has 2 divisors, whose sum is σ = 61439682. Its totient is φ = 61439680.

The previous prime is 61439659. The next prime is 61439687. The reversal of 61439681 is 18693416.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40132225 + 21307456 = 6335^2 + 4616^2 .

It is a cyclic number.

It is not a de Polignac number, because 61439681 - 2⁶ = 61439617 is a prime.

It is a super-2 number, since 2×61439681² = 7549668802763522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (61439687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30719840 + 30719841.

It is an arithmetic number, because the mean of its divisors is an integer number (30719841).

Almost surely, 2^61439681 is an apocalyptic number.

It is an amenable number.

61439681 is a deficient number, since it is larger than the sum of its proper divisors (1).

61439681 is an equidigital number, since it uses as much as digits as its factorization.

61439681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 38.

The square root of 61439681 is about 7838.3468282540. The cubic root of 61439681 is about 394.5932489736.

The spelling of 61439681 in words is "sixty-one million, four hundred thirty-nine thousand, six hundred eighty-one".