21016970 has 32 divisors (see below), whose sum is σ = 40960080. Its totient is φ = 7718400.

The previous prime is 21016949. The next prime is 21016979. The reversal of 21016970 is 7961012.

It can be written as a sum of positive squares in 8 ways, for example, as 3869089 + 17147881 = 1967^2 + 4141^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is not an unprimeable number, because it can be changed into a prime (21016979) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34670 + ... + 35270.

Almost surely, 2^21016970 is an apocalyptic number.

21016970 is a deficient number, since it is larger than the sum of its proper divisors (19943110).

21016970 is a wasteful number, since it uses less digits than its factorization.

21016970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 890.

The product of its (nonzero) digits is 756, while the sum is 26.

The square root of 21016970 is about 4584.4268998426. The cubic root of 21016970 is about 275.9667134120.

Adding to 21016970 its reverse (7961012), we get a palindrome (28977982).

The spelling of 21016970 in words is "twenty-one million, sixteen thousand, nine hundred seventy".