61721071 has 2 divisors, whose sum is σ = 61721072. Its totient is φ = 61721070.

The previous prime is 61721059. The next prime is 61721123. The reversal of 61721071 is 17012716.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61721071 - 2¹⁷ = 61589999 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61721171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30860535 + 30860536.

It is an arithmetic number, because the mean of its divisors is an integer number (30860536).

Almost surely, 2^61721071 is an apocalyptic number.

61721071 is a deficient number, since it is larger than the sum of its proper divisors (1).

61721071 is an equidigital number, since it uses as much as digits as its factorization.

61721071 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 588, while the sum is 25.

The square root of 61721071 is about 7856.2758989231. The cubic root of 61721071 is about 395.1947360037.

Adding to 61721071 its reverse (17012716), we get a palindrome (78733787).

The spelling of 61721071 in words is "sixty-one million, seven hundred twenty-one thousand, seventy-one".