1221690254 has 4 divisors (see below), whose sum is σ = 1832535384. Its totient is φ = 610845126.

The previous prime is 1221690109. The next prime is 1221690269. The reversal of 1221690254 is 4520961221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 4520961221 = 7 ⋅645851603.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221690254.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 305422562 + ... + 305422565.

It is an arithmetic number, because the mean of its divisors is an integer number (458133846).

Almost surely, 2^1221690254 is an apocalyptic number.

1221690254 is a deficient number, since it is larger than the sum of its proper divisors (610845130).

1221690254 is an equidigital number, since it uses as much as digits as its factorization.

1221690254 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610845129.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 1221690254 is about 34952.6859339880. The cubic root of 1221690254 is about 1069.0229687304.

The spelling of 1221690254 in words is "one billion, two hundred twenty-one million, six hundred ninety thousand, two hundred fifty-four".