61888781 has 2 divisors, whose sum is σ = 61888782. Its totient is φ = 61888780.

The previous prime is 61888763. The next prime is 61888793. The reversal of 61888781 is 18788816.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57304900 + 4583881 = 7570^2 + 2141^2 .

It is a cyclic number.

It is not a de Polignac number, because 61888781 - 2²² = 57694477 is a prime.

It is a super-2 number, since 2×61888781² = 7660442427331922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61888711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30944390 + 30944391.

It is an arithmetic number, because the mean of its divisors is an integer number (30944391).

Almost surely, 2^61888781 is an apocalyptic number.

It is an amenable number.

61888781 is a deficient number, since it is larger than the sum of its proper divisors (1).

61888781 is an equidigital number, since it uses as much as digits as its factorization.

61888781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 172032, while the sum is 47.

The square root of 61888781 is about 7866.9422903692. The cubic root of 61888781 is about 395.5523565468.

The spelling of 61888781 in words is "sixty-one million, eight hundred eighty-eight thousand, seven hundred eighty-one".