21148569 has 48 divisors (see below), whose sum is σ = 35642880. Its totient is φ = 11975040.

The previous prime is 21148559. The next prime is 21148573. The reversal of 21148569 is 96584112.

It is not a de Polignac number, because 21148569 - 2¹³ = 21140377 is a prime.

It is a super-2 number, since 2×21148569² = 894523941495522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21148529) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 77904 + ... + 78174.

It is an arithmetic number, because the mean of its divisors is an integer number (742560).

Almost surely, 2^21148569 is an apocalyptic number.

21148569 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21148569 is a deficient number, since it is larger than the sum of its proper divisors (14494311).

21148569 is a wasteful number, since it uses less digits than its factorization.

21148569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342 (or 339 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 21148569 is about 4598.7573321496. The cubic root of 21148569 is about 276.5415093329.

The spelling of 21148569 in words is "twenty-one million, one hundred forty-eight thousand, five hundred sixty-nine".