61721623 has 2 divisors, whose sum is σ = 61721624. Its totient is φ = 61721622.

The previous prime is 61721603. The next prime is 61721659. The reversal of 61721623 is 32612716.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61721623 - 2²¹ = 59624471 is a prime.

It is equal to p_3658060 and since 61721623 and 3658060 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 61721591 and 61721600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61721603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30860811 + 30860812.

It is an arithmetic number, because the mean of its divisors is an integer number (30860812).

Almost surely, 2^61721623 is an apocalyptic number.

61721623 is a deficient number, since it is larger than the sum of its proper divisors (1).

61721623 is an equidigital number, since it uses as much as digits as its factorization.

61721623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 28.

The square root of 61721623 is about 7856.3110299937. The cubic root of 61721623 is about 395.1959141364.

The spelling of 61721623 in words is "sixty-one million, seven hundred twenty-one thousand, six hundred twenty-three".