21739380437 has 4 divisors (see below), whose sum is σ = 21747485760. Its totient is φ = 21731275116.

The previous prime is 21739380427. The next prime is 21739380463. The reversal of 21739380437 is 73408393712.

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 not a de Polignac number, because 21739380437 - 2¹⁶ = 21739314901 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21739380391 and 21739380400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21739380427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4048637 + ... + 4054002.

It is an arithmetic number, because the mean of its divisors is an integer number (5436871440).

Almost surely, 2^21739380437 is an apocalyptic number.

It is an amenable number.

21739380437 is a deficient number, since it is larger than the sum of its proper divisors (8105323).

21739380437 is an equidigital number, since it uses as much as digits as its factorization.

21739380437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8105322.

The product of its (nonzero) digits is 762048, while the sum is 47.

The spelling of 21739380437 in words is "twenty-one billion, seven hundred thirty-nine million, three hundred eighty thousand, four hundred thirty-seven".