1861220407 has 2 divisors, whose sum is σ = 1861220408. Its totient is φ = 1861220406.

The previous prime is 1861220369. The next prime is 1861220437. The reversal of 1861220407 is 7040221681.

It is a strong prime.

It is an emirp because it is prime and its reverse (7040221681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1861220407 - 2¹⁹ = 1860696119 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1861220437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 930610203 + 930610204.

It is an arithmetic number, because the mean of its divisors is an integer number (930610204).

Almost surely, 2^1861220407 is an apocalyptic number.

1861220407 is a deficient number, since it is larger than the sum of its proper divisors (1).

1861220407 is an equidigital number, since it uses as much as digits as its factorization.

1861220407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 1861220407 is about 43141.8637404552. The cubic root of 1861220407 is about 1230.0778603190.

The spelling of 1861220407 in words is "one billion, eight hundred sixty-one million, two hundred twenty thousand, four hundred seven".