61890509 has 2 divisors, whose sum is σ = 61890510. Its totient is φ = 61890508.

The previous prime is 61890497. The next prime is 61890533. The reversal of 61890509 is 90509816.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61669609 + 220900 = 7853^2 + 470^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61890509 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61890209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30945254 + 30945255.

It is an arithmetic number, because the mean of its divisors is an integer number (30945255).

Almost surely, 2^61890509 is an apocalyptic number.

It is an amenable number.

61890509 is a deficient number, since it is larger than the sum of its proper divisors (1).

61890509 is an equidigital number, since it uses as much as digits as its factorization.

61890509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440, while the sum is 38.

The square root of 61890509 is about 7867.0521162631. The cubic root of 61890509 is about 395.5560379254.

The spelling of 61890509 in words is "sixty-one million, eight hundred ninety thousand, five hundred nine".