1217215730 has 16 divisors (see below), whose sum is σ = 2192189400. Its totient is φ = 486619392.

The previous prime is 1217215711. The next prime is 1217215757. The reversal of 1217215730 is 375127121.

1217215730 = T₂₂₀₆₃ + T₂₂₀₆₄ + ... + T₂₂₀₆₇.

It can be written as a sum of positive squares in 4 ways, for example, as 1003559041 + 213656689 = 31679^2 + 14617^2 .

It is a super-2 number, since 2×1217215730² = 2963228266718865800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1217215693 and 1217215702.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13655 + ... + 51194.

Almost surely, 2^1217215730 is an apocalyptic number.

1217215730 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1217215730 is a deficient number, since it is larger than the sum of its proper divisors (974973670).

1217215730 is a wasteful number, since it uses less digits than its factorization.

1217215730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66733.

The product of its (nonzero) digits is 2940, while the sum is 29.

The square root of 1217215730 is about 34888.6189179222. The cubic root of 1217215730 is about 1067.7162488994.

The spelling of 1217215730 in words is "one billion, two hundred seventeen million, two hundred fifteen thousand, seven hundred thirty".