63720421 has 2 divisors, whose sum is σ = 63720422. Its totient is φ = 63720420.

The previous prime is 63720409. The next prime is 63720427. The reversal of 63720421 is 12402736.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37822500 + 25897921 = 6150^2 + 5089^2 .

It is a cyclic number.

It is not a de Polignac number, because 63720421 - 2¹⁵ = 63687653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (63720427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31860210 + 31860211.

It is an arithmetic number, because the mean of its divisors is an integer number (31860211).

Almost surely, 2^63720421 is an apocalyptic number.

It is an amenable number.

63720421 is a deficient number, since it is larger than the sum of its proper divisors (1).

63720421 is an equidigital number, since it uses as much as digits as its factorization.

63720421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 63720421 is about 7982.5071875946. The cubic root of 63720421 is about 399.4166935474.

The spelling of 63720421 in words is "sixty-three million, seven hundred twenty thousand, four hundred twenty-one".