21011556045 has 64 divisors (see below), whose sum is σ = 37350802944. Its totient is φ = 10032168960.

The previous prime is 21011556037. The next prime is 21011556053. The reversal of 21011556045 is 54065511012.

It is an interprime number because it is at equal distance from previous prime (21011556037) and next prime (21011556053).

It is not a de Polignac number, because 21011556045 - 2³ = 21011556037 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1051669 + ... + 1071461.

It is an arithmetic number, because the mean of its divisors is an integer number (583606296).

Almost surely, 2^21011556045 is an apocalyptic number.

It is an amenable number.

21011556045 is a deficient number, since it is larger than the sum of its proper divisors (16339246899).

21011556045 is a wasteful number, since it uses less digits than its factorization.

21011556045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20022.

The product of its (nonzero) digits is 6000, while the sum is 30.

The spelling of 21011556045 in words is "twenty-one billion, eleven million, five hundred fifty-six thousand, forty-five".