215126021251 has 4 divisors (see below), whose sum is σ = 215817745104. Its totient is φ = 214434297400.

The previous prime is 215126021219. The next prime is 215126021321. The reversal of 215126021251 is 152120621512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 215126021251 - 2⁵ = 215126021219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215126021651) 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, 345861460 + ... + 345862081.

It is an arithmetic number, because the mean of its divisors is an integer number (53954436276).

Almost surely, 2^215126021251 is an apocalyptic number.

215126021251 is a deficient number, since it is larger than the sum of its proper divisors (691723853).

215126021251 is an equidigital number, since it uses as much as digits as its factorization.

215126021251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 691723852.

The product of its (nonzero) digits is 2400, while the sum is 28.

Adding to 215126021251 its reverse (152120621512), we get a palindrome (367246642763).

The spelling of 215126021251 in words is "two hundred fifteen billion, one hundred twenty-six million, twenty-one thousand, two hundred fifty-one".