21489151 has 2 divisors, whose sum is σ = 21489152. Its totient is φ = 21489150.

The previous prime is 21489137. The next prime is 21489179. The reversal of 21489151 is 15198412.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21489151 - 2¹⁷ = 21358079 is a prime.

It is a super-2 number, since 2×21489151² = 923567221401602, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21489101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10744575 + 10744576.

It is an arithmetic number, because the mean of its divisors is an integer number (10744576).

Almost surely, 2^21489151 is an apocalyptic number.

21489151 is a deficient number, since it is larger than the sum of its proper divisors (1).

21489151 is an equidigital number, since it uses as much as digits as its factorization.

21489151 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 31.

The square root of 21489151 is about 4635.6392223727. The cubic root of 21489151 is about 278.0181095116.

The spelling of 21489151 in words is "twenty-one million, four hundred eighty-nine thousand, one hundred fifty-one".