21154156 has 6 divisors (see below), whose sum is σ = 37019780. Its totient is φ = 10577076.

The previous prime is 21154153. The next prime is 21154157. The reversal of 21154156 is 65145112.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21154156.

It is not an unprimeable number, because it can be changed into a prime (21154153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2644266 + ... + 2644273.

Almost surely, 2^21154156 is an apocalyptic number.

It is an amenable number.

21154156 is a deficient number, since it is larger than the sum of its proper divisors (15865624).

21154156 is a wasteful number, since it uses less digits than its factorization.

21154156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5288543 (or 5288541 counting only the distinct ones).

The product of its digits is 1200, while the sum is 25.

The square root of 21154156 is about 4599.3647387438. The cubic root of 21154156 is about 276.5658593078.

Adding to 21154156 its reverse (65145112), we get a palindrome (86299268).

The spelling of 21154156 in words is "twenty-one million, one hundred fifty-four thousand, one hundred fifty-six".