15978223 has 2 divisors, whose sum is σ = 15978224. Its totient is φ = 15978222.

The previous prime is 15978211. The next prime is 15978239. The reversal of 15978223 is 32287951.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15978223 is a prime.

It is a super-2 number, since 2×15978223² = 510607220475458, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15978253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7989111 + 7989112.

It is an arithmetic number, because the mean of its divisors is an integer number (7989112).

Almost surely, 2^15978223 is an apocalyptic number.

15978223 is a deficient number, since it is larger than the sum of its proper divisors (1).

15978223 is an equidigital number, since it uses as much as digits as its factorization.

15978223 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30240, while the sum is 37.

The square root of 15978223 is about 3997.2769481236. The cubic root of 15978223 is about 251.8698359870.

The spelling of 15978223 in words is "fifteen million, nine hundred seventy-eight thousand, two hundred twenty-three".