20987479 has 2 divisors, whose sum is σ = 20987480. Its totient is φ = 20987478.

The previous prime is 20987453. The next prime is 20987489. The reversal of 20987479 is 97478902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20987479 - 2¹⁵ = 20954711 is a prime.

It is a super-3 number, since 3×20987479³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20987429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10493739 + 10493740.

It is an arithmetic number, because the mean of its divisors is an integer number (10493740).

Almost surely, 2^20987479 is an apocalyptic number.

20987479 is a deficient number, since it is larger than the sum of its proper divisors (1).

20987479 is an equidigital number, since it uses as much as digits as its factorization.

20987479 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 254016, while the sum is 46.

The square root of 20987479 is about 4581.2093381552. The cubic root of 20987479 is about 275.8375742136.

The spelling of 20987479 in words is "twenty million, nine hundred eighty-seven thousand, four hundred seventy-nine".