102009475721 has 2 divisors, whose sum is σ = 102009475722. Its totient is φ = 102009475720.

The previous prime is 102009475697. The next prime is 102009475739. The reversal of 102009475721 is 127574900201.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 100945998400 + 1063477321 = 317720^2 + 32611^2 .

It is a cyclic number.

It is not a de Polignac number, because 102009475721 - 2¹⁴ = 102009459337 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (102009475121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51004737860 + 51004737861.

It is an arithmetic number, because the mean of its divisors is an integer number (51004737861).

Almost surely, 2^102009475721 is an apocalyptic number.

It is an amenable number.

102009475721 is a deficient number, since it is larger than the sum of its proper divisors (1).

102009475721 is an equidigital number, since it uses as much as digits as its factorization.

102009475721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 35280, while the sum is 38.

The spelling of 102009475721 in words is "one hundred two billion, nine million, four hundred seventy-five thousand, seven hundred twenty-one".