21172042837 has 8 divisors (see below), whose sum is σ = 23107587552. Its totient is φ = 19238300400.

The previous prime is 21172042819. The next prime is 21172042891. The reversal of 21172042837 is 73824027112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21172042837 - 2¹¹ = 21172040789 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21172042796 and 21172042805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21172042807) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 425943 + ... + 473044.

It is an arithmetic number, because the mean of its divisors is an integer number (2888448444).

Almost surely, 2^21172042837 is an apocalyptic number.

It is an amenable number.

21172042837 is a deficient number, since it is larger than the sum of its proper divisors (1935544715).

21172042837 is a wasteful number, since it uses less digits than its factorization.

21172042837 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 901139.

The product of its (nonzero) digits is 37632, while the sum is 37.

Adding to 21172042837 its reverse (73824027112), we get a palindrome (94996069949).

The spelling of 21172042837 in words is "twenty-one billion, one hundred seventy-two million, forty-two thousand, eight hundred thirty-seven".