19901821653 has 24 divisors (see below), whose sum is σ = 32857501248. Its totient is φ = 11371188672.

The previous prime is 19901821633. The next prime is 19901821661. The reversal of 19901821653 is 35612810991.

It is not a de Polignac number, because 19901821653 - 2¹⁴ = 19901805269 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19901821599 and 19901821608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19901821633) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1063425 + ... + 1081977.

It is an arithmetic number, because the mean of its divisors is an integer number (1369062552).

Almost surely, 2^19901821653 is an apocalyptic number.

It is an amenable number.

19901821653 is a deficient number, since it is larger than the sum of its proper divisors (12955679595).

19901821653 is a wasteful number, since it uses less digits than its factorization.

19901821653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35593 (or 35590 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 45.

The spelling of 19901821653 in words is "nineteen billion, nine hundred one million, eight hundred twenty-one thousand, six hundred fifty-three".