63970021 has 4 divisors (see below), whose sum is σ = 64399500. Its totient is φ = 63540544.

The previous prime is 63970007. The next prime is 63970069. The reversal of 63970021 is 12007936.

63970021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 36784225 + 27185796 = 6065^2 + 5214^2 .

It is a cyclic number.

It is not a de Polignac number, because 63970021 - 2⁵ = 63969989 is a prime.

It is a super-4 number, since 4×63970021⁴ (a number of 32 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63970721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 214516 + ... + 214813.

It is an arithmetic number, because the mean of its divisors is an integer number (16099875).

Almost surely, 2^63970021 is an apocalyptic number.

It is an amenable number.

63970021 is a deficient number, since it is larger than the sum of its proper divisors (429479).

63970021 is a wasteful number, since it uses less digits than its factorization.

63970021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 429478.

The product of its (nonzero) digits is 2268, while the sum is 28.

The square root of 63970021 is about 7998.1260930295. The cubic root of 63970021 is about 399.9375339955.

Adding to 63970021 its reverse (12007936), we get a palindrome (75977957).

The spelling of 63970021 in words is "sixty-three million, nine hundred seventy thousand, twenty-one".