21927407 has 2 divisors, whose sum is σ = 21927408. Its totient is φ = 21927406.

The previous prime is 21927391. The next prime is 21927413. The reversal of 21927407 is 70472912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21927407 - 2⁴ = 21927391 is a prime.

It is a super-2 number, since 2×21927407² = 961622355487298, which contains 22 as substring.

It is equal to p_1384943 and since 21927407 and 1384943 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21927457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10963703 + 10963704.

It is an arithmetic number, because the mean of its divisors is an integer number (10963704).

Almost surely, 2^21927407 is an apocalyptic number.

21927407 is a deficient number, since it is larger than the sum of its proper divisors (1).

21927407 is an equidigital number, since it uses as much as digits as its factorization.

21927407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 21927407 is about 4682.6709258713. The cubic root of 21927407 is about 279.8953988536.

The spelling of 21927407 in words is "twenty-one million, nine hundred twenty-seven thousand, four hundred seven".