1221020947 has 2 divisors, whose sum is σ = 1221020948. Its totient is φ = 1221020946.

The previous prime is 1221020939. The next prime is 1221020953. The reversal of 1221020947 is 7490201221.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1221020947 - 2³ = 1221020939 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221020447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610510473 + 610510474.

It is an arithmetic number, because the mean of its divisors is an integer number (610510474).

Almost surely, 2^1221020947 is an apocalyptic number.

1221020947 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221020947 is an equidigital number, since it uses as much as digits as its factorization.

1221020947 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 1221020947 is about 34943.1101506434. The cubic root of 1221020947 is about 1068.8277104923.

The spelling of 1221020947 in words is "one billion, two hundred twenty-one million, twenty thousand, nine hundred forty-seven".