21209394837 has 64 divisors (see below), whose sum is σ = 31364057088. Its totient is φ = 12690432000.

The previous prime is 21209394827. The next prime is 21209394853. The reversal of 21209394837 is 73849390212.

It is not a de Polignac number, because 21209394837 - 2¹⁶ = 21209329301 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21209394827) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 39203787 + ... + 39204327.

It is an arithmetic number, because the mean of its divisors is an integer number (490063392).

Almost surely, 2^21209394837 is an apocalyptic number.

It is an amenable number.

21209394837 is a deficient number, since it is larger than the sum of its proper divisors (10154662251).

21209394837 is a wasteful number, since it uses less digits than its factorization.

21209394837 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 910.

The product of its (nonzero) digits is 653184, while the sum is 48.

The spelling of 21209394837 in words is "twenty-one billion, two hundred nine million, three hundred ninety-four thousand, eight hundred thirty-seven".