21340051 has 2 divisors, whose sum is σ = 21340052. Its totient is φ = 21340050.

The previous prime is 21340019. The next prime is 21340063. The reversal of 21340051 is 15004312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21340051 - 2⁵ = 21340019 is a prime.

It is not a weakly prime, because it can be changed into another prime (21340091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10670025 + 10670026.

It is an arithmetic number, because the mean of its divisors is an integer number (10670026).

Almost surely, 2^21340051 is an apocalyptic number.

21340051 is a deficient number, since it is larger than the sum of its proper divisors (1).

21340051 is an equidigital number, since it uses as much as digits as its factorization.

21340051 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21340051 is about 4619.5293050266. The cubic root of 21340051 is about 277.3736177472.

Adding to 21340051 its reverse (15004312), we get a palindrome (36344363).

The spelling of 21340051 in words is "twenty-one million, three hundred forty thousand, fifty-one".