1216626461 has 4 divisors (see below), whose sum is σ = 1217136000. Its totient is φ = 1216116924.

The previous prime is 1216626431. The next prime is 1216626511. The reversal of 1216626461 is 1646266121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1646266121 = 263 ⋅6259567.

It is a cyclic number.

It is not a de Polignac number, because 1216626461 - 2¹⁴ = 1216610077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216626431) 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, 251171 + ... + 255968.

It is an arithmetic number, because the mean of its divisors is an integer number (304284000).

Almost surely, 2^1216626461 is an apocalyptic number.

It is an amenable number.

1216626461 is a deficient number, since it is larger than the sum of its proper divisors (509539).

1216626461 is an equidigital number, since it uses as much as digits as its factorization.

1216626461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 509538.

The product of its digits is 20736, while the sum is 35.

The square root of 1216626461 is about 34880.1728923467. The cubic root of 1216626461 is about 1067.5439229295.

The spelling of 1216626461 in words is "one billion, two hundred sixteen million, six hundred twenty-six thousand, four hundred sixty-one".