1221270015 has 32 divisors (see below), whose sum is σ = 2258288640. Its totient is φ = 552017664.

The previous prime is 1221270013. The next prime is 1221270023. The reversal of 1221270015 is 5100721221.

It is not a de Polignac number, because 1221270015 - 2¹ = 1221270013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 1221269973 and 1221270000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221270013) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 55999 + ... + 74688.

It is an arithmetic number, because the mean of its divisors is an integer number (70571520).

Almost surely, 2^1221270015 is an apocalyptic number.

1221270015 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1221270015 is a deficient number, since it is larger than the sum of its proper divisors (1037018625).

1221270015 is a wasteful number, since it uses less digits than its factorization.

1221270015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130791.

The product of its (nonzero) digits is 280, while the sum is 21.

The square root of 1221270015 is about 34946.6738760644. The cubic root of 1221270015 is about 1068.9003799203.

Adding to 1221270015 its reverse (5100721221), we get a palindrome (6321991236).

The spelling of 1221270015 in words is "one billion, two hundred twenty-one million, two hundred seventy thousand, fifteen".