1621752091 has 2 divisors, whose sum is σ = 1621752092. Its totient is φ = 1621752090.

The previous prime is 1621752079. The next prime is 1621752101. The reversal of 1621752091 is 1902571261.

It is a strong prime.

It is an emirp because it is prime and its reverse (1902571261) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1621752091 is a prime.

It is a super-3 number, since 3×1621752091³ (a number of 29 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (1621752001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810876045 + 810876046.

It is an arithmetic number, because the mean of its divisors is an integer number (810876046).

Almost surely, 2^1621752091 is an apocalyptic number.

1621752091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621752091 is an equidigital number, since it uses as much as digits as its factorization.

1621752091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7560, while the sum is 34.

The square root of 1621752091 is about 40270.9832385553. The cubic root of 1621752091 is about 1174.8835474751.

The spelling of 1621752091 in words is "one billion, six hundred twenty-one million, seven hundred fifty-two thousand, ninety-one".