21787437394 has 8 divisors (see below), whose sum is σ = 32693326848. Its totient is φ = 10889661780.

The previous prime is 21787437377. The next prime is 21787437481. The reversal of 21787437394 is 49373478712.

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

It is a super-2 number, since 2×21787437394² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2021742 + ... + 2032489.

It is an arithmetic number, because the mean of its divisors is an integer number (4086665856).

Almost surely, 2^21787437394 is an apocalyptic number.

21787437394 is a deficient number, since it is larger than the sum of its proper divisors (10905889454).

21787437394 is a wasteful number, since it uses less digits than its factorization.

21787437394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4056920.

The product of its digits is 7112448, while the sum is 55.

The spelling of 21787437394 in words is "twenty-one billion, seven hundred eighty-seven million, four hundred thirty-seven thousand, three hundred ninety-four".