21075747025 has 12 divisors (see below), whose sum is σ = 27671216652. Its totient is φ = 15868797440.

The previous prime is 21075747019. The next prime is 21075747031. The reversal of 21075747025 is 52074757012.

It is an interprime number because it is at equal distance from previous prime (21075747019) and next prime (21075747031).

It can be written as a sum of positive squares in 6 ways, for example, as 32182929 + 21043564096 = 5673^2 + 145064^2 .

It is not a de Polignac number, because 21075747025 - 2³¹ = 18928263377 is a prime.

It is a super-2 number, since 2×21075747025² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24794572 + ... + 24795421.

It is an arithmetic number, because the mean of its divisors is an integer number (2305934721).

Almost surely, 2^21075747025 is an apocalyptic number.

21075747025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21075747025 is a deficient number, since it is larger than the sum of its proper divisors (6595469627).

21075747025 is a wasteful number, since it uses less digits than its factorization.

21075747025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49590020 (or 49590015 counting only the distinct ones).

The product of its (nonzero) digits is 137200, while the sum is 40.

The spelling of 21075747025 in words is "twenty-one billion, seventy-five million, seven hundred forty-seven thousand, twenty-five".