21070437 has 16 divisors (see below), whose sum is σ = 28873152. Its totient is φ = 13662720.

The previous prime is 21070403. The next prime is 21070447. The reversal of 21070437 is 73407012.

It is not a de Polignac number, because 21070437 - 2¹⁶ = 21004901 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21070447) 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, 17158 + ... + 18344.

It is an arithmetic number, because the mean of its divisors is an integer number (1804572).

Almost surely, 2^21070437 is an apocalyptic number.

It is an amenable number.

21070437 is a deficient number, since it is larger than the sum of its proper divisors (7802715).

21070437 is a wasteful number, since it uses less digits than its factorization.

21070437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1348.

The product of its (nonzero) digits is 1176, while the sum is 24.

The square root of 21070437 is about 4590.2545681040. The cubic root of 21070437 is about 276.2005342660.

Adding to 21070437 its reverse (73407012), we get a palindrome (94477449).

The spelling of 21070437 in words is "twenty-one million, seventy thousand, four hundred thirty-seven".