21107780237 has 4 divisors (see below), whose sum is σ = 21125040480. Its totient is φ = 21090519996.

The previous prime is 21107780207. The next prime is 21107780263. The reversal of 21107780237 is 73208770112.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21107780237 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21107780237.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21107780207) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8628287 + ... + 8630732.

It is an arithmetic number, because the mean of its divisors is an integer number (5281260120).

Almost surely, 2^21107780237 is an apocalyptic number.

It is an amenable number.

21107780237 is a deficient number, since it is larger than the sum of its proper divisors (17260243).

21107780237 is a wasteful number, since it uses less digits than its factorization.

21107780237 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17260242.

The product of its (nonzero) digits is 32928, while the sum is 38.

The spelling of 21107780237 in words is "twenty-one billion, one hundred seven million, seven hundred eighty thousand, two hundred thirty-seven".