215257540 has 12 divisors (see below), whose sum is σ = 452040876. Its totient is φ = 86103008.

The previous prime is 215257487. The next prime is 215257543. The reversal of 215257540 is 45752512.

It can be written as a sum of positive squares in 2 ways, for example, as 36554116 + 178703424 = 6046^2 + 13368^2 .

It is not an unprimeable number, because it can be changed into a prime (215257543) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5381419 + ... + 5381458.

It is an arithmetic number, because the mean of its divisors is an integer number (37670073).

Almost surely, 2^215257540 is an apocalyptic number.

215257540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

215257540 is an abundant number, since it is smaller than the sum of its proper divisors (236783336).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

215257540 is a wasteful number, since it uses less digits than its factorization.

215257540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10762886 (or 10762884 counting only the distinct ones).

The product of its (nonzero) digits is 14000, while the sum is 31.

The square root of 215257540 is about 14671.6577113835. The cubic root of 215257540 is about 599.3117478539.

The spelling of 215257540 in words is "two hundred fifteen million, two hundred fifty-seven thousand, five hundred forty".