19864849 has 3 divisors (see below), whose sum is σ = 19869307. Its totient is φ = 19860392.

The previous prime is 19864837. The next prime is 19864903. The reversal of 19864849 is 94846891.

The square root of 19864849 is 4457.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 94846891 = 97 ⋅977803.

It can be written as a sum of positive squares in only one way, i.e., 13950225 + 5914624 = 3735^2 + 2432^2 .

It is not a de Polignac number, because 19864849 - 2²¹ = 17767697 is a prime.

It is a super-2 number, since 2×19864849² = 789224451585602, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19864349) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2229 + ... + 6685.

Almost surely, 2^19864849 is an apocalyptic number.

19864849 is the 4457-th square number.

19864849 is the 2229-th centered octagonal number.

It is an amenable number.

19864849 is a deficient number, since it is larger than the sum of its proper divisors (4458).

19864849 is an frugal number, since it uses more digits than its factorization.

19864849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8914 (or 4457 counting only the distinct ones).

The product of its digits is 497664, while the sum is 49.

The cubic root of 19864849 is about 270.8289521237.

Multiplying 19864849 by its sum of digits (49), we get a square (973377601 = 31199²).

The spelling of 19864849 in words is "nineteen million, eight hundred sixty-four thousand, eight hundred forty-nine".