20151947 has 2 divisors, whose sum is σ = 20151948. Its totient is φ = 20151946.

The previous prime is 20151931. The next prime is 20151949. The reversal of 20151947 is 74915102.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20151947 - 2⁴ = 20151931 is a prime.

It is a super-2 number, since 2×20151947² = 812201935781618, which contains 22 as substring.

Together with 20151949, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_1279640 and since 20151947 and 1279640 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (20151949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10075973 + 10075974.

It is an arithmetic number, because the mean of its divisors is an integer number (10075974).

Almost surely, 2^20151947 is an apocalyptic number.

20151947 is a deficient number, since it is larger than the sum of its proper divisors (1).

20151947 is an equidigital number, since it uses as much as digits as its factorization.

20151947 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 20151947 is about 4489.0920017304. The cubic root of 20151947 is about 272.1274408212.

The spelling of 20151947 in words is "twenty million, one hundred fifty-one thousand, nine hundred forty-seven".