215378649 has 8 divisors (see below), whose sum is σ = 319079520. Its totient is φ = 143585748.

The previous prime is 215378641. The next prime is 215378663. The reversal of 215378649 is 946873512.

215378649 is a `hidden beast` number, since 215 + 378 + 64 + 9 = 666.

It is not a de Polignac number, because 215378649 - 2³ = 215378641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (215378641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3988467 + ... + 3988520.

It is an arithmetic number, because the mean of its divisors is an integer number (39884940).

Almost surely, 2^215378649 is an apocalyptic number.

It is an amenable number.

215378649 is a deficient number, since it is larger than the sum of its proper divisors (103700871).

215378649 is an equidigital number, since it uses as much as digits as its factorization.

215378649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7976996 (or 7976990 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 215378649 is about 14675.7844424072. The cubic root of 215378649 is about 599.4241224519.

The spelling of 215378649 in words is "two hundred fifteen million, three hundred seventy-eight thousand, six hundred forty-nine".