61689281 has 2 divisors, whose sum is σ = 61689282. Its totient is φ = 61689280.

The previous prime is 61689263. The next prime is 61689317. The reversal of 61689281 is 18298616.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42250000 + 19439281 = 6500^2 + 4409^2 .

It is a cyclic number.

It is not a de Polignac number, because 61689281 - 2²² = 57494977 is a prime.

It is a super-2 number, since 2×61689281² = 7611134780593922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (61689581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30844640 + 30844641.

It is an arithmetic number, because the mean of its divisors is an integer number (30844641).

Almost surely, 2^61689281 is an apocalyptic number.

It is an amenable number.

61689281 is a deficient number, since it is larger than the sum of its proper divisors (1).

61689281 is an equidigital number, since it uses as much as digits as its factorization.

61689281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41472, while the sum is 41.

The square root of 61689281 is about 7854.2524150934. The cubic root of 61689281 is about 395.1268748016.

The spelling of 61689281 in words is "sixty-one million, six hundred eighty-nine thousand, two hundred eighty-one".