215721151 has 2 divisors, whose sum is σ = 215721152. Its totient is φ = 215721150.

The previous prime is 215721127. The next prime is 215721179. The reversal of 215721151 is 151127512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 215721151 - 2⁵ = 215721119 is a prime.

It is a super-2 number, since 2×215721151² = 93071229977529602, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215721851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107860575 + 107860576.

It is an arithmetic number, because the mean of its divisors is an integer number (107860576).

Almost surely, 2^215721151 is an apocalyptic number.

215721151 is a deficient number, since it is larger than the sum of its proper divisors (1).

215721151 is an equidigital number, since it uses as much as digits as its factorization.

215721151 is an evil number, because the sum of its binary digits is even.

The product of its digits is 700, while the sum is 25.

The square root of 215721151 is about 14687.4487573574. The cubic root of 215721151 is about 599.7416952952.

Adding to 215721151 its reverse (151127512), we get a palindrome (366848663).

The spelling of 215721151 in words is "two hundred fifteen million, seven hundred twenty-one thousand, one hundred fifty-one".