21143970 has 32 divisors (see below), whose sum is σ = 56384640. Its totient is φ = 5638320.

The previous prime is 21143951. The next prime is 21143977. The reversal of 21143970 is 7934112.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21143977) 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, 38886 + ... + 39425.

It is an arithmetic number, because the mean of its divisors is an integer number (1762020).

Almost surely, 2^21143970 is an apocalyptic number.

21143970 is an abundant number, since it is smaller than the sum of its proper divisors (35240670).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21143970 is a wasteful number, since it uses less digits than its factorization.

21143970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78327 (or 78321 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21143970 is about 4598.2572785785. The cubic root of 21143970 is about 276.5214621671.

It can be divided in two parts, 2114 and 3970, that added together give a square (6084 = 78²).

The spelling of 21143970 in words is "twenty-one million, one hundred forty-three thousand, nine hundred seventy".