20152421 has 2 divisors, whose sum is σ = 20152422. Its totient is φ = 20152420.

The previous prime is 20152411. The next prime is 20152441. The reversal of 20152421 is 12425102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15888196 + 4264225 = 3986^2 + 2065^2 .

It is a cyclic number.

It is not a de Polignac number, because 20152421 - 2¹⁴ = 20136037 is a prime.

It is a super-2 number, since 2×20152421² = 812240144322482, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20152421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20152411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10076210 + 10076211.

It is an arithmetic number, because the mean of its divisors is an integer number (10076211).

Almost surely, 2^20152421 is an apocalyptic number.

It is an amenable number.

20152421 is a deficient number, since it is larger than the sum of its proper divisors (1).

20152421 is an equidigital number, since it uses as much as digits as its factorization.

20152421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 20152421 is about 4489.1447960608. The cubic root of 20152421 is about 272.1295744015.

Adding to 20152421 its reverse (12425102), we get a palindrome (32577523).

The spelling of 20152421 in words is "twenty million, one hundred fifty-two thousand, four hundred twenty-one".