21529157 has 16 divisors (see below), whose sum is σ = 24967152. Its totient is φ = 18385920.

The previous prime is 21529133. The next prime is 21529169. The reversal of 21529157 is 75192512.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 5134756 + 16394401 = 2266^2 + 4049^2 .

It is a cyclic number.

It is not a de Polignac number, because 21529157 - 2⁶ = 21529093 is a prime.

It is a super-2 number, since 2×21529157² = 927009202261298, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21529757) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12683 + ... + 14279.

It is an arithmetic number, because the mean of its divisors is an integer number (1560447).

Almost surely, 2^21529157 is an apocalyptic number.

It is an amenable number.

21529157 is a deficient number, since it is larger than the sum of its proper divisors (3437995).

21529157 is a wasteful number, since it uses less digits than its factorization.

21529157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1688.

The product of its digits is 6300, while the sum is 32.

The square root of 21529157 is about 4639.9522626855. The cubic root of 21529157 is about 278.1905298101.

The spelling of 21529157 in words is "twenty-one million, five hundred twenty-nine thousand, one hundred fifty-seven".