215977493 has 2 divisors, whose sum is σ = 215977494. Its totient is φ = 215977492.

The previous prime is 215977477. The next prime is 215977501. The reversal of 215977493 is 394779512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 202265284 + 13712209 = 14222^2 + 3703^2 .

It is a cyclic number.

It is not a de Polignac number, because 215977493 - 2⁴ = 215977477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215977423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107988746 + 107988747.

It is an arithmetic number, because the mean of its divisors is an integer number (107988747).

Almost surely, 2^215977493 is an apocalyptic number.

It is an amenable number.

215977493 is a deficient number, since it is larger than the sum of its proper divisors (1).

215977493 is an equidigital number, since it uses as much as digits as its factorization.

215977493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 476280, while the sum is 47.

The square root of 215977493 is about 14696.1727330622. The cubic root of 215977493 is about 599.9791594613.

The spelling of 215977493 in words is "two hundred fifteen million, nine hundred seventy-seven thousand, four hundred ninety-three".