21851380037 has 8 divisors (see below), whose sum is σ = 22828028160. Its totient is φ = 20891717280.

The previous prime is 21851380009. The next prime is 21851380079. The reversal of 21851380037 is 73008315812.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21851380037 - 2¹⁶ = 21851314501 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21851380087) 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, 4243712 + ... + 4248857.

It is an arithmetic number, because the mean of its divisors is an integer number (2853503520).

Almost surely, 2^21851380037 is an apocalyptic number.

It is an amenable number.

21851380037 is a deficient number, since it is larger than the sum of its proper divisors (976648123).

21851380037 is an equidigital number, since it uses as much as digits as its factorization.

21851380037 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8492683.

The product of its (nonzero) digits is 40320, while the sum is 38.

Adding to 21851380037 its reverse (73008315812), we get a palindrome (94859695849).

The spelling of 21851380037 in words is "twenty-one billion, eight hundred fifty-one million, three hundred eighty thousand, thirty-seven".