19690649 has 4 divisors (see below), whose sum is σ = 21480720. Its totient is φ = 17900580.

The previous prime is 19690639. The next prime is 19690667. The reversal of 19690649 is 94609691.

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, and also an emirpimes, since its reverse is a distinct semiprime: 94609691 = 11 ⋅8600881.

It is a cyclic number.

It is not a de Polignac number, because 19690649 - 2⁴ = 19690633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19690609) 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, 895019 + ... + 895040.

It is an arithmetic number, because the mean of its divisors is an integer number (5370180).

Almost surely, 2^19690649 is an apocalyptic number.

It is an amenable number.

19690649 is a deficient number, since it is larger than the sum of its proper divisors (1790071).

19690649 is a wasteful number, since it uses less digits than its factorization.

19690649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1790070.

The product of its (nonzero) digits is 104976, while the sum is 44.

The square root of 19690649 is about 4437.4146752360. The cubic root of 19690649 is about 270.0349703219.

The spelling of 19690649 in words is "nineteen million, six hundred ninety thousand, six hundred forty-nine".