21156077 has 2 divisors, whose sum is σ = 21156078. Its totient is φ = 21156076.

The previous prime is 21156071. The next prime is 21156127. The reversal of 21156077 is 77065112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14032516 + 7123561 = 3746^2 + 2669^2 .

It is a cyclic number.

It is not a de Polignac number, because 21156077 - 2⁶ = 21156013 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21156071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10578038 + 10578039.

It is an arithmetic number, because the mean of its divisors is an integer number (10578039).

Almost surely, 2^21156077 is an apocalyptic number.

It is an amenable number.

21156077 is a deficient number, since it is larger than the sum of its proper divisors (1).

21156077 is an equidigital number, since it uses as much as digits as its factorization.

21156077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2940, while the sum is 29.

The square root of 21156077 is about 4599.5735671908. The cubic root of 21156077 is about 276.5742306642.

It can be divided in two parts, 2115 and 6077, that added together give a 13-th power (8192 = 2¹³).

The spelling of 21156077 in words is "twenty-one million, one hundred fifty-six thousand, seventy-seven".