19978733 has 2 divisors, whose sum is σ = 19978734. Its totient is φ = 19978732.

The previous prime is 19978667. The next prime is 19978753. The reversal of 19978733 is 33787991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12482089 + 7496644 = 3533^2 + 2738^2 .

It is an emirp because it is prime and its reverse (33787991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19978733 - 2¹² = 19974637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19978753) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9989366 + 9989367.

It is an arithmetic number, because the mean of its divisors is an integer number (9989367).

Almost surely, 2^19978733 is an apocalyptic number.

It is an amenable number.

19978733 is a deficient number, since it is larger than the sum of its proper divisors (1).

19978733 is an equidigital number, since it uses as much as digits as its factorization.

19978733 is an evil number, because the sum of its binary digits is even.

The product of its digits is 285768, while the sum is 47.

The square root of 19978733 is about 4469.7575996915. The cubic root of 19978733 is about 271.3455150044.

The spelling of 19978733 in words is "nineteen million, nine hundred seventy-eight thousand, seven hundred thirty-three".