20978467 has 4 divisors (see below), whose sum is σ = 21171040. Its totient is φ = 20785896.

The previous prime is 20978431. The next prime is 20978473. The reversal of 20978467 is 76487902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 76487902 = 2 ⋅38243951.

It is a cyclic number.

It is not a de Polignac number, because 20978467 - 2²³ = 12589859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20978267) 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, 96123 + ... + 96340.

It is an arithmetic number, because the mean of its divisors is an integer number (5292760).

Almost surely, 2^20978467 is an apocalyptic number.

20978467 is a deficient number, since it is larger than the sum of its proper divisors (192573).

20978467 is a wasteful number, since it uses less digits than its factorization.

20978467 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192572.

The product of its (nonzero) digits is 169344, while the sum is 43.

The square root of 20978467 is about 4580.2256494631. The cubic root of 20978467 is about 275.7980871125.

The spelling of 20978467 in words is "twenty million, nine hundred seventy-eight thousand, four hundred sixty-seven".