21151413 has 6 divisors (see below), whose sum is σ = 30552054. Its totient is φ = 14100936.

The previous prime is 21151343. The next prime is 21151433. The reversal of 21151413 is 31415112.

It can be written as a sum of positive squares in only one way, i.e., 17791524 + 3359889 = 4218^2 + 1833^2 .

It is not a de Polignac number, because 21151413 - 2¹² = 21147317 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21151433) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1175070 + ... + 1175087.

It is an arithmetic number, because the mean of its divisors is an integer number (5092009).

Almost surely, 2^21151413 is an apocalyptic number.

It is an amenable number.

21151413 is a deficient number, since it is larger than the sum of its proper divisors (9400641).

21151413 is a wasteful number, since it uses less digits than its factorization.

21151413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2350163 (or 2350160 counting only the distinct ones).

The product of its digits is 120, while the sum is 18.

The square root of 21151413 is about 4599.0665357222. The cubic root of 21151413 is about 276.5539049517.

Adding to 21151413 its reverse (31415112), we get a palindrome (52566525).

The spelling of 21151413 in words is "twenty-one million, one hundred fifty-one thousand, four hundred thirteen".