1225402991 has 2 divisors, whose sum is σ = 1225402992. Its totient is φ = 1225402990.

The previous prime is 1225402979. The next prime is 1225403021. The reversal of 1225402991 is 1992045221.

It is a weak prime.

It is an emirp because it is prime and its reverse (1992045221) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1225402991 is a prime.

It is a super-2 number, since 2×1225402991² = 3003224980703492162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1225402921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 612701495 + 612701496.

It is an arithmetic number, because the mean of its divisors is an integer number (612701496).

Almost surely, 2^1225402991 is an apocalyptic number.

1225402991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1225402991 is an equidigital number, since it uses as much as digits as its factorization.

1225402991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 35.

The square root of 1225402991 is about 35005.7565408891. The cubic root of 1225402991 is about 1070.1047997623.

The spelling of 1225402991 in words is "one billion, two hundred twenty-five million, four hundred two thousand, nine hundred ninety-one".